Orders of magnitude (length)

The following are examples of orders of magnitude for different lengths.

Detailed list

To help compare different orders of magnitude, the following list describes various lengths between metres and metres. Metres are used in these tables to provide a common reference point, but metric prefixes above "k" are not commonly used with metres. So for example, 1.21 Gm would more commonly be written as 1.21 million km or 1.21 × 10⁶ km. Interplanetary distances are also commonly measured in astronomical units. Distances on the interstellar or larger scale are typically measured in light-years or parsecs.

Atomic to cellular scale

Factor	Multiple	Value	Item
10⁻¹⁵	1 femtometre	1 fm	Approximate limit of the gluon-mediated color force between quarks
10⁻¹⁵	1 femtometre	1.5 fm	Effective cross section radius of an 11 MeV proton
10⁻¹⁵	1 femtometre	2.81794 fm	Classical [electron radius]
10⁻¹⁵	1 femtometre	3 fm	Approximate limit of the meson-mediated nuclear binding force
10⁻¹⁵	1 femtometre	750 to 822.25 fm	Longest wavelength of gamma rays
10⁻¹²	1 picometre	1.75 to 15 fm	diameter range of the atomic nucleus
10⁻¹²	1 picometre	1 pm	Distance between atomic nuclei in a white dwarf
10⁻¹²	1 picometre	2.4 pm	Compton wavelength of electron
10⁻¹²	1 picometre	5 pm	Wavelength of shortest X-rays
10⁻¹¹	10 pm	28 pm	Radius of helium atom
10⁻¹¹	10 pm	53 pm	Bohr radius
10⁻¹⁰	100 pm	100 pm	1 ångström
10⁻¹⁰	100 pm	154 pm	Length of a typical covalent bond
10⁻¹⁰	100 pm	280 pm	Average size of the water molecule
10⁻¹⁰	100 pm	500 pm	Width of protein α helix
10⁻⁹	1 nanometre	1 nm	diameter of a carbon nanotube diameter of smallest transistor gate
10⁻⁹	1 nanometre	2 nm	diameter of the DNA helix
10⁻⁹	1 nanometre	2.5 nm	Smallest microprocessor transistor gate oxide thickness
10⁻⁹	1 nanometre	3.4 nm	Length of a DNA turn
10⁻⁹	1 nanometre	6–10 nm	Thickness of cell membrane
10⁻⁸	10 nm	10 nm	Upper range of thickness of cell wall in Gram-negative bacteria
10⁻⁸	10 nm	10 nm	, the 10 nanometre was the smallest semiconductor device fabrication node
10⁻⁸	10 nm	40 nm	Extreme ultraviolet wavelength
10⁻⁸	10 nm	50 nm	Flying height of the head of a hard disk
10⁻⁷	100 nm	121.6 nm	Wavelength of the Lyman-alpha line
10⁻⁷	100 nm	120 nm	Typical diameter of the human immunodeficiency virus
10⁻⁷	100 nm	400–700 nm	Approximate wavelength range of visible light

Cellular to human scale

Factor	Multiple	Value	Item
10⁻⁶	1 micrometre	1–4 μm	Typical length of a bacterium
10⁻⁶	1 micrometre	4 μm	Typical diameter of spider silk
10⁻⁶	1 micrometre	7 μm	Typical size of a red blood cell
10⁻⁵	10 μm	10 μm	Typical size of a fog, mist, or cloud water droplet
10⁻⁵	10 μm	10 μm	Width of transistors in the Intel 4004, the world's first commercial microprocessor
10⁻⁵	10 μm	12 μm	Width of acrylic fiber
10⁻⁵	10 μm	17–181 μm	Width range of human hair
10⁻⁴	100 μm	340 μm	Size of a pixel on a 17-inch monitor with a resolution of 1024×768
10⁻⁴	100 μm	560 μm	Thickness of the central area of a human cornea or, diameter of a grain of salt.
10⁻⁴	100 μm	750 μm	Maximum diameter of Thiomargarita namibiensis, the second largest bacterium ever discovered
10⁻³	1 millimetre	~5 mm	Length of an average flea is 1–10 mm
10⁻³	1 millimetre	2.54 mm	One-tenth inch; distance between pins in DIP electronic components
10⁻³	1 millimetre	5.70 mm	Approximate diameter of the projectile in 5.56×45mm NATO ammunition
10⁻²	1 centimetre	20 mm	Approximate width of an adult human finger
10⁻²	1 centimetre	54 mm × 86 mm	Dimensions of a credit card, according to the ISO/IEC 7810 ID-1 standard
10⁻²	1 centimetre	73–75 mm	diameter of a baseball, according to Major League Baseball guidelines
10⁻¹	1 decimetre	120 mm	diameter of a compact disc
10⁻¹	1 decimetre	660 mm	Length of the longest pine cones, produced by the sugar pine
10⁻¹	1 decimetre	900 mm	Average length of a rapier, a fencing sword

Human to astronomical scale

Factor	Multiple	Value	Item
1	1 metre	1 m	Since 2019, defined as the length of the path travelled by light in a vacuum during a time interval of 1/299,792,458 of a second, where the second is defined by a hyperfine transition frequency of caesium.
1	1 metre	2.72 m	Height of Robert Wadlow, tallest-known human.
1	1 metre	8.38 m	Length of a London bus
10¹	1 decametre	33 m	Length of the longest-known blue whale
10¹	1 decametre	52 m	Height of the Niagara Falls
10¹	1 decametre	93.47 m	Height of the Statue of Liberty
10²	1 hectometre	105 m	Length of a typical football field
10²	1 hectometre	137 m	Height of the Great Pyramid of Giza
10²	1 hectometre	300 m	Height of the Eiffel Tower, one of the famous monuments of Paris
10²	1 hectometre	979 m	Height of the Salto Angel, the world's highest free-falling waterfall
10³	1 kilometre	2.3 km	Length of the Three Gorges Dam, the largest dam in the world
10³	1 kilometre	3.1 km	Narrowest width of the Strait of Messina, separating Italy and Sicily
10³	1 kilometre	8.848 km	Height of Mount Everest, the highest mountain on Earth
10⁴	10 km	10.9 km	Depth of the Challenger Deep in the Mariana Trench, the deepest-known point on Earth's surface
10⁴	10 km	27 km	Circumference of the Large Hadron Collider, the largest and highest energy particle accelerator
10⁴	10 km	42.195 km	Length of a marathon
10⁵	100 km	100 km	The distance the IAU considers to be the limit to space, called the Karman line
10⁵	100 km	163 km	Length of the Suez Canal, connecting the Mediterranean Sea to the Red Sea
10⁵	100 km	491 km	Length of the Pyrenees, the mountain range separating Spain and France
10⁵	100 km	600 km	Thermosphere height
10⁵	100 km	974.6 km	Greatest diameter of the dwarf planet Ceres.
10⁶	1 megametre	2.38 Mm	diameter of dwarf planet Pluto, formerly the smallest planet category in the Solar System
10⁶	1 megametre	3.48 Mm	diameter of the Moon
10⁶	1 megametre	5.2 Mm	Typical distance covered by the winner of the 24 Hours of Le Mans automobile endurance race
10⁶	1 megametre	6.259 Mm	Length of the Great Wall of China
10⁶	1 megametre	6.371 Mm	Average radius of Earth
10⁶	1 megametre	6.378 Mm	Equatorial radius of Earth
10⁶	1 megametre	6.6 Mm	Approximate length of the two longest rivers, the Nile and the Amazon
10⁶	1 megametre	7.821 Mm	Length of the Trans-Canada Highway
10⁶	1 megametre	9.288 Mm	Length of the Trans-Siberian Railway, longest in the world

1 quectometre and less

The is a unit of length in the metric system equal to.
To help compare different orders of magnitude, this section lists lengths shorter than 10⁻³⁰ m.

0 quectometres — gravitational singularity
1.6 × 10⁻⁵ quectometres – the Planck length
1 qm – 1 quectometre, the smallest named subdivision of the metre in the SI base unit of length, one nonillionth of a metre.

1 rontometre

The is a unit of length in the metric system equal to.

10 rontometres

10 rm – the length of one side of a square whose area is one shed, a unit of target cross section used in nuclear physics

1 yoctometre

The is a unit of length in the metric system equal to.

2 ym – the effective cross-section radius of 1 MeV neutrinos as measured by Clyde Cowan and Frederick Reines.

1 zeptometre

The is a unit of length in the metric system equal to.
To help compare different orders of magnitude, this section lists lengths between 10⁻²¹ m and 10⁻²⁰ m.

2 zm – the upper bound for the width of a cosmic string in string theory.
2 zm – radius of effective cross section for a 20 GeV neutrino scattering off a nucleon
7 zm – radius of effective cross section for a 250 GeV neutrino scattering off a nucleon

10 zeptometres

To help compare different orders of magnitude, this section lists lengths between 10⁻²⁰ m and 10⁻¹⁹ m.

100 zeptometres

To help compare different orders of magnitude, this section lists lengths between 10⁻¹⁹ m and 10⁻¹⁸ m.

177 zm – de Broglie wavelength of protons at the Large Hadron Collider

1 attometre

The is a unit of length in the metric system equal to.
To help compare different orders of magnitude, this section lists lengths between 10⁻¹⁸ m and 10⁻¹⁷ m.

1 am – sensitivity of the LIGO detector for gravitational waves
1 am – upper limit for the size of quarks and electrons

10 attometres

To help compare different orders of magnitude, this section lists lengths between 10⁻¹⁷ m and 10⁻¹⁶ m.

10–100 am – range of the weak force
86 am – charge radius of a Bottom eta meson

100 attometres

To help compare different orders of magnitude, this section lists lengths between 10⁻¹⁶ m and 10⁻¹⁵ m.

831 am – approximate proton radius

1 femtometre (or 1 fermi)

The is a unit of length in the metric system equal to.
In particle physics, this unit is sometimes called a [fermi (unit)|], also with abbreviation "fm". To help compare different orders of magnitude, this section lists lengths between 10⁻¹⁵ metres and 10⁻¹⁴ metres.

1 fm – diameter of a neutron, approximate range-limit of the color force carried between quarks by gluons
1.5 fm – diameter of the scattering cross section of an 11 MeV proton with a target proton
1.75 fm – the effective charge diameter of a proton
2.81794 fm – classical electron radius
3 fm – approximate range-limit of the nuclear binding force mediated by mesons
7 fm – the radius of the effective scattering cross section for a gold nucleus scattering a 6 MeV alpha particle over 140 degrees

10 femtometres

To help compare different orders of magnitude, this section lists lengths between 10⁻¹⁴ m and 10⁻¹³ m.

1.75 to 15 fm – diameter range of the atomic nucleus
10 fm – the length of one side of a square whose area is one barn, a unit of target cross section used in nuclear physics
30.8568 fm – 1 quectoparsec

100 femtometres

To help compare different orders of magnitude, this section lists lengths between 10⁻¹³ m and 10⁻¹² m.

570 fm – typical distance from the atomic nucleus of the two innermost electrons in the uranium atom, the heaviest naturally occurring atom

1 picometre

The is a unit of length in the metric system equal to .
To help compare different orders of magnitude this section lists lengths between 10⁻¹² and 10⁻¹¹ m.

1 pm – distance between atomic nuclei in a white dwarf
1 pm – reference value of particle displacement in acoustics
2.4 pm – the Compton wavelength of an electron
5 pm – shorter X-ray wavelengths

10 picometres

To help compare different orders of magnitude this section lists lengths between 10⁻¹¹ and 10⁻¹⁰ m.

25 pm – approximate radius of a helium atom, the smallest neutral atom
30.8568 pm – 1 rontoparsec
50 pm – Bohr radius: approximate radius of a hydrogen atom
~50 pm – best resolution of a high-resolution transmission electron microscope
60 pm – radius of a carbon atom
93 pm – length of a diatomic carbon molecule
96 pm – H–O bond length in a water molecule

100 picometres

To help compare different orders of magnitude this section lists lengths between 10⁻¹⁰ and 10⁻⁹ m.

100 pm – 1 ångström
100 pm – covalent radius of sulfur atom
120 pm – van der Waals radius of a neutral hydrogen atom
120 pm – radius of a gold atom
126 pm – covalent radius of ruthenium atom
135 pm – covalent radius of technetium atom
150 pm – length of a typical covalent bond
153 pm – covalent radius of silver atom
155 pm – covalent radius of zirconium atom
175 pm – covalent radius of thulium atom
200 pm – highest resolution of a typical electron microscope
225 pm – covalent radius of caesium atom
280 pm – average size of the water molecule
298 pm – radius of a caesium atom, calculated to be the largest atomic radius
340 pm – thickness of single layer graphene
356.68 pm – width of diamond unit cell
403 pm – width of lithium fluoride unit cell
500 pm – width of protein α helix
543 pm – silicon lattice spacing
560 pm – width of sodium chloride unit cell
700 pm – width of glucose molecule
700 pm – diameter of a buckyball
780 pm – mean width of quartz unit cell
820 pm – mean width of ice unit cell
900 pm – mean width of coesite unit cell

1 nanometre

The is a unit of length in the metric system equal to .
To help compare different orders of magnitude, this section lists lengths between 10⁻⁹ and 10⁻⁸ m.

1 nm – diameter of a carbon nanotube
1 nm – roughly the length of a sucrose molecule, calculated by Albert Einstein
2.3 nm – length of a phospholipid
2.3 nm – smallest gate oxide thickness in microprocessors
3 nm – width of a DNA helix
3 nm – flying height of the head of a hard disk
3 nm – the average half-pitch of a memory cell manufactured circa 2022
3.4 nm – length of a DNA turn
3.8 nm – size of an albumin molecule
5 nm – size of the gate length of a 16 nm processor
5 nm – the average half-pitch of a memory cell manufactured circa 2019–2020
6 nm – length of a phospholipid bilayer
6–10 nm – thickness of cell membrane
6.8 nm – width of a haemoglobin molecule
7 nm – diameter of actin filaments
7 nm – the average half-pitch of a memory cell manufactured circa 2018
10 nm – thickness of cell wall in Gram-negative bacteria

10 nanometres

To help compare different orders of magnitude this section lists lengths between 10⁻⁸ and 10⁻⁷ m.

10 nm – shortest extreme ultraviolet wavelength or longest X-ray wavelength
10 nm – the average length of a nanowire
10 nm – lower size of tobacco smoke
10 nm – the average half-pitch of a memory cell manufactured circa 2016 –2017
13 nm – the length of the wavelength that is used for EUV lithography
14 nm – length of a porcine circovirus
14 nm – the average half-pitch of a memory cell manufactured circa 2013
15 nm – length of an antibody
18 nm – diameter of tobacco mosaic virus
20 nm – length of a nanobe, could be one of the smallest forms of life
20–80 nm – thickness of cell wall in Gram-positive bacteria
20 nm – thickness of bacterial flagellum
22 nm – the average half-pitch of a memory cell manufactured circa 2011–2012
22 nm – smallest feature size of production microprocessors in September 2009
25 nm – diameter of a microtubule
30 nm – lower size of cooking oil smoke
30.8568 nm – 1 yoctoparsec
32 nm – the average half-pitch of a memory cell manufactured circa 2009–2010
40 nm – extreme ultraviolet wavelength
45 nm – the average half-pitch of a memory cell manufactured circa 2007–2008
50 nm – upper size for airborne virus particles
50 nm – flying height of the head of a hard disk
65 nm – the average half-pitch of a memory cell manufactured circa 2005–2006
58 nm – height of a T7 bacteriophage
90 nm – human immunodeficiency virus (HIV)
90 nm – the average half-pitch of a memory cell manufactured circa 2002–2003
100 nm – length of a mesoporous silica nanoparticle

100 nanometres

To help compare different orders of magnitude, this section lists lengths between 10⁻⁷ and 10⁻⁶ m.

100 nm – greatest particle size that can fit through a surgical mask
100 nm – 90% of particles in wood smoke are smaller than this.
120 nm – greatest particle size that can fit through a ULPA filter
120 nm – diameter of a human immunodeficiency virus
120 nm – approximate diameter of SARS-CoV-2
125 nm – standard depth of pits on compact discs
180 nm – typical length of the rabies virus
200 nm — typical diameter of the chickenpox virus
200 nm – typical size of a Mycoplasma bacterium, among the smallest bacteria
300 nm – greatest particle size that can fit through a HEPA filter
300–400 nm – near ultraviolet wavelength
400–420 nm – wavelength of violet light
420–440 nm – wavelength of indigo light
440–500 nm – wavelength of blue light
500–520 nm – wavelength of cyan light
520–565 nm – wavelength of green light
565–590 nm – wavelength of yellow light
590–625 nm – wavelength of orange light
625–700 nm – wavelength of red light
700 nm–1.4 μm – wavelength of near-infrared radiation

1 micrometre (or 1 micron)

The is a unit of length in the metric system equal to .
To help compare different orders of magnitude, this section lists some items with lengths between 10⁻⁶ and 10⁻⁵ m.

~0.7–300 μm – wavelength of infrared radiation
1 μm – the side of a square of area 10⁻¹² m²
1 μm – edge of cube of volume 10⁻¹⁸ m³
1–10 μm – diameter of a typical bacterium
1 μm – length of a lysosome
1 μm – diameter of aerosol
1–2 μm – anthrax spore
2 μm – length of an average E. coli bacteria
3–4 μm – size of a typical yeast cell
5 μm – length of a typical human spermatozoon's head
6 μm – thickness of the tape in a 120-minute compact cassette
7 μm – diameter of the nucleus of a typical eukaryotic cell
about 7 μm – diameter of human red blood cells
3–8 μm – width of strand of spider web silk
5–10 μm – width of a chloroplast
8–11 μm – size of a ground-level fog or mist droplet
7–12 μm – the diameter of human white blood cells
8–10 μm – the diameter of human macrophages

10 micrometres

To help compare different orders of magnitude, this section lists lengths between 10⁻⁵ m and 10⁻⁴ m.

10 μm – width of cotton fibre
10 μm – tolerance of the mold used to manufacture a Lego brick
10 μm – transistor width of the Intel 4004, the world's first commercial microprocessor
10 μm – mean longest dimension of a human red blood cell
5–20 μm – dust mite excreta
10.6 μm – wavelength of light emitted by a carbon dioxide laser
15 μm – width of silk fibre
17 μm – minimum width of a strand of human hair
17.6 μm – one twip, a unit of length in typography
10 to 55 μm – width of wool fibre
20 μm — diameter of a cloud droplet
25 μm — diameter of grass pollen
25.4 μm – 1/1,000 inch, commonly referred to as 1 mil in the U.S. and 1 thou in the U.K.
30 μm – length of a human skin cell
30.8568 μm – 1 zeptoparsec
50 μm – typical length of Euglena gracilis, a flagellate protist
50 μm – typical length of a human liver cell, an average-sized body cell
50 μm – length of a silt particle
60 μm – length of a sperm cell
78 μm — width of a pixel on the display of the iPhone 4, marketed as Retina Display
70 to 180 μm – thickness of paper

100 micrometres

To help compare different orders of magnitude, this section lists lengths between 10⁻⁴ m and 10⁻³ m. The term myriometre is deprecated; the decimal metric prefix myrio- is obsolete and was not included among the prefixes when the International System of Units was introduced in 1960.

100 μm – 1/10 of a millimetre
100 μm – 0.00394 inches
100 μm – smallest distance that can be seen with the naked eye
100 μm – average diameter of a strand of human hair
100 μm – thickness of a coat of paint
100 μm – length of a dust particle
120 μm – the geometric mean of the Planck length and the diameter of the observable universe:
120 μm – diameter of a human ovum
170 μm – length of the largest mammalian sperm cell
170 μm – length of the largest sperm cell in nature, belonging to the Drosophila bifurca fruit fly
181 μm – maximum width of a strand of human hair
100–400 μm – length of Demodex mites living in human hair follicles
175–200 μm – typical thickness of a solar cell.
200 μm – typical length of Paramecium caudatum, a ciliate protist
200 μm – nominal width of the smallest commonly available mechanical pencil lead
250–300 μm – length of a dust mite
340 μm – length of a pixel on a 17-inch monitor with a resolution of 1024×768
500 μm – typical length of Amoeba proteus, an amoeboid protist
500 μm — length of a tardigrade
500 μm – MEMS micro-engine
500 μm – average length of a grain of sand
500 μm – average length of a grain of salt
500 μm – average length of a grain of sugar
560 μm – thickness of the central area of a human cornea
750 μm – diameter of a Thiomargarita namibiensis, which used to be considered the largest bacteria known
760 μm – thickness of an identification card

1 millimetre

The is a unit of length in the metric system equal to .
To help compare different orders of magnitude, this section lists lengths between 10⁻³ m and 10⁻² m.

1.0 mm – 1/1,000 of a metre
1.0 mm – 0.03937 inches or 5/127
1.0 mm – side of a square of area 1 mm²
1.0 mm – diameter of a pinhead
1.5 mm – average length of a flea
2 mm — diameter of a rain droplet
2.54 mm – distance between pins on old dual in-line package electronic components
5 mm – length of an average red ant
5 mm – diameter of an average grain of rice
5.56×45mm NATO – standard ammunition size
6 mm – approximate width of a pencil
7 mm – length of a Paedophryne amauensis, the smallest-known vertebrate
7 mm – length of a human tooth
7.1 mm – length of a sunflower seed
7.62×51mm NATO – common military ammunition size
8 mm – width of old-format home movie film
8 mm – length of a Paedocypris progenetica, the smallest-known fish

1 centimetre

The is a unit of length in the metric system equal to .
To help compare different orders of magnitude, this section lists lengths between 10⁻² m and 10⁻¹ m.

1 cm – 10 millimetres
1 cm – 0.39 inches
1 cm – edge of a square of area 1 cm²
1 cm – edge of a cube of volume 1 mL
1 cm – length of a coffee bean
1 cm – approximate width of average fingernail
1.2 cm – length of a bee
1.2 cm – diameter of a die
1.5 cm – length of a very large mosquito
1.6 cm – length of a Jaragua Sphaero, a very small reptile
1.7 cm – length of a Thorius arboreus, the smallest salamander
1.77 cm – approximate diameter of a Black Hole the mass of earth.
2 cm – approximate width of an adult human finger
2.4 cm – diameter of a human eye
2.54 cm – 1 inch
3.08568 cm – 1 attoparsec
3.4 cm – length of a quail egg
3.5 cm – width of film commonly used in motion pictures and still photography
3.78 cm – amount of distance the Moon moves away from Earth each year
4.3 cm – minimum diameter of a golf ball
5 cm – usual diameter of a chicken egg
5 cm – height of a hummingbird, the smallest-known bird
5.08 cm – 2 inches,
5.5 × 5.5 × 5.5 cm – dimensions of a standard 3x3x3 Rubik's cube
6.1 cm – average height of an apple
7.3–7.5 cm – diameter of a baseball
8.6 cm × 5.4 cm – dimensions of a standard credit card
9 cm – length of a speckled padloper, the smallest-known turtle

1 decimetre

The is a unit of length in the metric system equal to .
To help compare different orders of magnitude, this section lists lengths between 10 centimetres and 100 centimetres.

Conversions

10 centimetres is equal to:

1 decimetre, a term not in common use
100 millimetres
3.9 inches
a side of a square of area 0.01 m²
the edge of a cube with a volume of m³

Wavelengths

10 cm = 1.0 dm – wavelength of the highest UHF radio frequency, 3 GHz
12 cm = 1.2 dm – wavelength of the 2.45 GHz ISM radio band
21 cm = 2.1 dm – wavelength of the 1.4 GHz hydrogen emission line, a hyperfine transition of the hydrogen atom
100 cm = 10 dm – wavelength of the lowest UHF radio frequency, 300 MHz

Human-defined scales and structures

10 cm = 1 dm — length of a kazoo instrument
10.16 cm = 1.016 dm – 1 hand used in measuring height of horses
12 cm = 1.2 dm – diameter of a compact disc
9-12 cm = 0.9-1.2dm — height of a soda can
15 cm = 1.5 dm – length of a Bic pen with cap on
20 cm = 2 dm — height of a water bottle
22 cm = 2.2 dm – diameter of a typical association football
30 cm = 3 dm – typical school-use ruler length
30.48 cm = 3.048 dm – 1 foot
60 cm = 6 dm – standard depth of a domestic kitchen worktop in Europe
60 cm = 6 dm — diameter of the LAGEOS satellite
90 cm = 9 dm – average length of a rapier, a fencing sword
91 cm = 9.1 dm — length of a shopping cart
91.44 cm = 9.144 dm – one yard

Nature

10 cm = 1 dm – diameter of the human cervix upon entering the second stage of labour
11 cm = 1.1 dm – length of an average potato in the U.S.
13 cm = 1.3 dm – body length of a Goliath birdeater
18.1 cm = 1.81 dm – Maximum overall length of the Hercules beetle, one of the largest beetle species
19 cm = 1.9 dm — length of an average male human hand
19 cm = 1.9 dm – length of a banana
20 cm = 2 dm — diameter of the Syringammina, one of the largest single-celled organisms
20 cm = 2 dm - average height of the Venus flytrap
26.3 cm = 2.6 dm – length of an average male human foot
29.98 cm = 2.998 dm – distance light in vacuum travels in one nanosecond
30 cm = 3.0 dm – maximum leg length of a Goliath birdeater
31 cm = 3.1 dm – wingspan of largest butterfly species Ornithoptera alexandrae
32 cm – length of the Goliath frog, the world's largest frog
46 cm = 4.6 dm – length of an average domestic cat
50 to 65 cm = 5–6.5 dm – a coati's tail
66 cm = 6.6 dm – length of the longest pine cones
80 cm = 8 dm - height of a chimpanzee
90 cm = 9 dm — length of a capybara, the largest rodent

Astronomical

84 cm = 8.4 dm – approximate diameter of 2008 TS26, a meteoroid

1 metre

To help compare different orders of magnitude, this section lists lengths between one metre and ten metres.
Light, in vacuum, travels 1 metre in, or of a second.

Conversions

1 metre is:

10 decimetres
100 centimetres
1,000 millimetres
39.37 inches
3.28 feet
1.1 yards
side of square with area 1 m²
edge of cube with surface area 6 m² and volume 1 m³
radius of circle with area π m²
radius of sphere with surface area 4π m² and volume 4/3π m³

Human-defined scales and structures

1 m – approximate height of the top part of a doorknob on a door
1 m – diameter of a very large beach ball
1 m – height of a typical washing machine
1.29 m – length of the Cross Island Chapel, the smallest church in the world
1.4 m – length of a Peel P50, the world's smallest car
1.4 m – length of a pool noodle
1.435 m – standard gauge of railway track used by about 60% of railways in the world = 4 ft 8 in
1.5 m – height of the Lasko pedestal fan
1.8 m – height of an average refrigerator
1.9 m – height of a vending machine
2 m – typical height of an average door
2.5 m – distance from the floor to the ceiling in an average residential house
2.7 m – length of the Starr Bumble Bee II, the smallest plane
2.77–3.44 m – wavelength of the broadcast radio FM band 87–108 MHz
2.8 m – height of a telephone booth
3.05 m – the length of an old Mini
6 m – height of an average typical house
8 m – length of the Tsar Bomba, the largest bomb ever detonated
8.38 m – the length of a London Bus

Sports

2.44 m – height of an association football goal
2.45 m – highest high jump by a human
3.05 m – height of the basket in basketball
8.95 m – longest long jump by a human

Nature

1 m – length of Rafflesia arnoldii, the largest flower in the world
1 m – height of Homo floresiensis
1 m — length of an ocelot, a type of cat
1.15 m – a pizote
1.5 m – height of an okapi
1.5 m — height of an orangutan
1.63 m – – height of average U.S. female human
1.75 m – – height of average U.S. male human
1.8 m — height of a gorilla
2 m — height of a kangaroo
2.1 m - average height of a moose, the largest living deer
2.4 m – wingspan of a mute swan
2.5 m – height of a sunflower
2.5 m - average length of a black mamba, the second longest venomous snake and the longest venomous snake in Africa
2.7 m – length of a leatherback sea turtle, the largest living turtle
2.72 m – – tallest-known human
3 m – length of a giant Gippsland earthworm
3 m – length of an Komodo dragon, the largest living lizard
3.3 m - wingspan of an Andean condor
3.63 m – the record wingspan for living birds
3.7 m – leg span of a Japanese spider crab
3.7 m – length of a southern [elephant seal], the largest living pinniped
4 m - average length of an king cobra, the longest venomous snake
4 m - length of a hippopotamus
5 m – length of an elephant
5.2 m – height of a giraffe
5.21 m - length of a green anaconda, the largest living snake
5.5 m – height of a Baluchitherium, the largest land mammal ever lived
6.5 m - length of an reticulated python, the longest living snake
6.5 m – wingspan of Argentavis, the largest flying bird known
6.7 m – length of a Microchaetus rappi
7.4 m – wingspan of Pelagornis, the bird with longest wingspan ever.
7.5 m – approximate length of the human gastrointestinal tract

Astronomical

3–6 m – approximate diameter of, a meteoroid
4.1 m – diameter of 2008 TC3, a small asteroid that flew into the Earth's atmosphere on 7 October 2008

1 decametre

The is a unit of length in the metric system equal to 10 metres.
To help compare different orders of magnitude, this section lists lengths between 10 and 100 metres.

Conversions

10 metres is equal to:

10 metres
100 decimetres
1,000 centimetres
10,000 millimetres
10,000,000 micrometres
32.8 feet
11 yards
side of a square with area 100 m²

Human-defined scales and structures

10 metres – wavelength of the highest shortwave radio frequency, 30 MHz
10.2 metres – length of the Panzer VIII Maus, the world's largest tank
12 metres – height of the Newby-McMahon Building, the world's littlest skyscraper
12 metres — length of a school bus and city bus
16 metres — length of a semi-truck
23 metres – height of Luxor Obelisk, located in the Place de la Concorde, Paris, France
25 metres – wavelength of the broadcast radio shortwave band at 12 MHz
29 metres – height of the Savudrija Lighthouse
30 metres – height of Christ the Redeemer
31 metres – wavelength of the broadcast radio shortwave band at 9.7 MHz
32 metres – length of one arcsecond of latitude on the surface of the Earth
33.3 metres – height of the De Noord, the tallest windmill in the world
34 metres – height of the Split Point Lighthouse in Aireys Inlet, Victoria, Australia
40 metres – wingspan of the Mil Mi-26, the largest helicopter
40 metres – average depth beneath the seabed of the Channel tunnel
49 metres – wavelength of the broadcast radio shortwave band at 6.1 MHz
50 metres – length of a road train
50 metres – height of the Arc de Triomphe
55 metres – height of the Leaning Tower of Pisa
18-55 metres — height of a Transmission tower
56 metres — height of the Space Shuttle
62 metres – wingspan of Concorde
62.5 metres – height of Pyramid of Djoser
64 metres – wingspan of a Boeing 747-400
69 metres – wingspan of an Antonov An-124 Ruslan
70 metres – length of the Bayeux Tapestry
70 metres – width of a typical association football field
73 metres – wingspan of a Airbus A380
73 metres – height of the Taj Mahal
77 metres – wingspan of a Boeing 747-8
88.4 metres – wingspan of an Antonov An-225 Mriya transport aircraft
93 metres – height of the Statue of Liberty
96 metres – height of Big Ben
100 metres – wavelength of the lowest shortwave radio frequency, 3 MHz

Sports

11 metres – approximate width of a doubles tennis court
15 metres – width of a standard FIBA basketball court
15.24 metres – width of an NBA basketball court
18.44 metres – distance between the front of the pitcher's rubber and the rear point of home plate on a baseball field
20 metres – length of cricket pitch
27.43 metres – distance between bases on a baseball field
28 metres – length of a standard FIBA basketball court
28.65 metres – length of an NBA basketball court
49 metres – width of an American football field
59.436 metres – width of a Canadian football field
70 metres – typical width of an association football field
91 metres – length of an American football field

Nature

10 metres – average length of human digestive tract
12 metres – height of a standard saguaro cactus
12 metres – length of a whale shark, largest living fish
12 metres – wingspan of a Quetzalcoatlus, a pterosaur
12.8 metres – length of a Titanoboa, the largest snake to have ever lived
13 metres – approximate length of a giant squid and colossal squid, the largest living invertebrates
15 metres – approximate distance the tropical circles of latitude are moving towards the equator and the polar circles are moving towards the poles each year due to a natural, gradual decrease in the Earth's axial tilt
16 metres – length of a sperm whale, the largest toothed whale
17 metres – length of an average-sized Megalodon, widely considered to be the largest shark to ever roam the waters
18 metres – height of a Sauroposeidon, the tallest-known dinosaur
20 metres – length of a Leedsichthys, the largest-known fish to have lived
21 metres – height of High Force waterfall in England
30.5 metres – length of the lion's mane jellyfish, the largest jellyfish in the world
33 metres – length of a blue whale, the largest animal on earth, living or extinct, in terms of mass
39 metres – length of a Supersaurus, the longest-known dinosaur and longest vertebrate
52 metres – height of Niagara Falls
55 metres – length of a bootlace worm, the longest-known animal
66 metres – highest possible sea level rise due to a complete melting of all ice on Earth
83 metres – height of a western hemlock
84 metres – height of General Sherman, the largest tree in the world

Astronomical

30 metres – diameter of, a rapidly spinning meteoroid
30.8568 metres – 1 femtoparsec
32 metres – approximate diameter of 2008 HJ, a small meteoroid

1 hectometre

The is a unit of length in the metric system equal to 100 metres.
To compare different orders of magnitude this section lists lengths between 100 metres and 1,000 metres.

Conversions

100 metres is equal to:

327.9 feet
one side of a 1 hectare square
a fifth of a modern li, a Chinese unit of measurement
the approximate distance travelled by light in 300 nanoseconds

Human-defined scales and structures

100 metres – wavelength of the highest medium wave radio frequency, 3 MHz
100 metres – spacing of location marker posts on British motorways
103 metres — length of the Spearhead-class expeditionary fast transport
109 metres — width of the International Space Station
110 metres – height of the Saturn V
122 metres – height of the Starship, the tallest rocket currently under development by SpaceX
138.8 metres – height of the Great Pyramid of Giza
139 metres – height of the world's tallest roller coaster, Kingda Ka
157 metres – height of the Cologne Cathedral
162 metres – height of the Ulm Minster, the tallest church building in the world
165 metres – height of the Dushanbe Flagpole, the tallest flagpole from May 2011 to September 2014
169 metres – height of the Washington Monument
171 metres – height of the Jeddah Flagpole, the tallest flagpole from September 2014 to December 2021
182 metres – height of the Statue of Unity, the world's tallest statue
187 metres – shortest wavelength of the broadcast radio AM band, 1600 kHz
192 metres – height of the Gateway Arch
200 metres — length of a high speed train
202 metres – height of the Cairo Flagpole, the tallest flagpole as of December 2021
202 metres – length of the Széchenyi Chain Bridge connecting Buda and Pest
220 metres – height of the Hoover Dam
225 metres — length of the Bagger 293
245 metres – length of the LZ 129 Hindenburg
270 metres – length of the Titanic
300 metres — length of an Aircraft carrier
318 metres – height of The New York Times Building
318.9 metres – height of the Chrysler Building
328 metres – height of Auckland's Sky Tower, the tallest free-standing structure in the Southern Hemisphere
330 metres – height of the Eiffel Tower
336 metres – height of the world's tallest bridge as of October 2023, the Millau Viaduct
364.75 metres – length of the Icon of the Seas
390 metres – height of the Empire State Building
400–800 metres – approximate heights of the world's tallest skyscrapers from 1931 to 2010
458 metres – length of the Knock Nevis, the world's largest supertanker
502 metres — length of the Overburden Conveyor Bridge F60
553.33 metres – height of the CN Tower, the tallest structure in North America
555 metres – longest wavelength of the broadcast radio AM band, 540 kHz
630 metres – height of the KVLY-TV mast, one of the tallest structures in the world
646 metres – height of the Warsaw radio mast, the world's tallest structure until its collapse in 1991
679 metres – height of Merdeka 118, the second tallest structure in Kuala Lumpur, Malaysia
828 metres – height of Burj Khalifa, world's tallest structure since 17 January 2009
1,000 metres – wavelength of the lowest mediumwave radio frequency, 300 kHz

Sports

100 metres – the distance a very fast human can run in about 10 seconds
100.584 metres – length of a Canadian football field between the goal lines
91.5 metres – 137 metres – length of a soccer field
105 metres – length of football pitch
105 metres – length of a typical football field
109.73 metres – total length of an American football field
110–150 metres – the width of an Australian football field
135–185 metres – the length of an Australian football field
137.16 metres – total length of a Canadian football field, including the end zones

Nature

115.5 metres – height of the world's tallest tree in 2007, the Hyperion sequoia
310 metres – maximum depth of Lake Geneva
340 metres – distance sound travels in air at sea level in one second; see Speed of sound
947 metres – height of the Tugela Falls, the highest waterfall in Africa
979 metres – height of the Angel Falls, the world's highest free-falling waterfall

Astronomical

270 metres – length of 99942 Apophis
535 metres – length of 25143 Itokawa, a small asteroid visited by a spacecraft

1 kilometre

The is a unit of length in the metric system equal to metres.
To help compare different orders of magnitude, this section lists lengths between 1 kilometre and 10 kilometres.

Conversions

1 kilometre is equal to:

1,000 metres
0.621371 miles
1,093.61 yards
3,280.84 feet
39,370.1 inches
100,000 centimetres
1,000,000 millimetres
Side of a square of area 1 km²
Radius of a circle of area π km²

Human-defined scales and structures

1 km – wavelength of the highest long wave radio frequency, 300 kHz
1.008 km – proposed height of the Jeddah Tower, a megatall skyscraper under construction in Saudi Arabia
1.280 km – span of the Golden Gate Bridge
1.609 km – 1 statute mile
1.852 km – 1 nautical mile, equal to 1 arcminute of latitude at the surface of the Earth
1.991 km – span of the Akashi Kaikyō Bridge
2.309 km – axial length of the Three Gorges Dam, the largest dam in the world located in China
3.991 km – length of the Akashi Kaikyō Bridge, longest suspension bridge in the world
4 km – width of Central Park
5.072 km – elevation of Tanggula Mountain Pass, below highest peak in the Tanggula Mountains, highest railway pass in the world
5.8 km – elevation of Cerro Aucanquilcha, highest road in the world, located in Chile
98 airports have paved runways from 4 km to 5.5 km in length.
8 km – length of Palm Jebel Ali, an artificial island built off the coast of Dubai
9.8 km – length of The World, an artificial archipelago that is also built off the coast of Dubai, whose islands resemble a world map

Nature

1.5 km – distance sound travels in water in one second

Geographical

1.637 km – deepest dive of Lake Baikal in Russia, the world's largest freshwater lake
2.228 km – height of Mount Kosciuszko, highest point on mainland Australia
Most of Manhattan is from 3 to 4 km wide.
3.776 km – height of Mount Fuji, highest peak in Japan
4.478 km – height of Matterhorn
4.509 km – height of Mount Wilhelm, highest peak in Papua New Guinea
4.810 km – height of Mont Blanc, highest peak in the Alps
4.884 km – height of Carstensz Pyramid, highest peak in Oceania
4.892 km – height of Mount Vinson, highest peak in Antarctica
5.610 km – height of Mount Damavand, highest peak in Iran
5.642 km – height of Mount Elbrus, highest peak in Europe
5.895 km – height of Mount Kilimanjaro, highest peak in Africa
6.081 km – height of Mount Logan, highest peak in Canada
6.190 km – height of Denali, highest peak in North America
6.959 km – height of Aconcagua, highest peak in South America
7.5 km – depth of Cayman Trench, deepest point in the Caribbean Sea
8.611 km – height of K2, second highest peak on Earth
8.848 km – height of Mount Everest, highest peak on Earth, on the border between Nepal and China

Astronomical

1 km – diameter of 1620 Geographos
1 km – very approximate size of the smallest-known moons of Jupiter
1.4 km – diameter of Dactyl, the first confirmed asteroid moon
4.8 km – diameter of 5535 Annefrank, an inner belt asteroid
5 km – diameter of 3753 Cruithne
5 km – length of PSR B1257+12
8 km – diameter of Themisto, one of Jupiter's moons
8 km – diameter of the Vela Pulsar
8.6 km – diameter of Callirrhoe, also known as Jupiter XVII
9.737 km – length of PSR B1919+21

10 kilometres (1 myriametre)

To help compare different orders of magnitude, this section lists lengths between 10 and 100 kilometres. The myriametre is a deprecated unit name; the decimal metric prefix myria- is obsolete and was not included among the prefixes when the International System of Units was introduced in 1960.

Conversions

10 kilometres is equal to:
File:Myriameterstein36RüdesheimRhein.JPG|thumb|Distance marker on the Rhine: 36 myriametres from Basel. The stated distance is ; the comma is the decimal separator in Germany.

10,000 metres
About 6.2 miles
1 mil , now standardized as 10 km:
*1 mil, the unit of measure commonly used in Norway and Sweden used to be 11,295 m in Norway and 10,688 m in Sweden.
farsang, unit of measure commonly used in Iran and Turkey

Sports

42.195 km – length of the marathon

Human-defined scales and structures

18 km – cruising altitude of Concorde
27 km – circumference of the Large Hadron Collider, the largest and highest energy particle accelerator
34.668 km – highest manned balloon flight
38.422 km – length of the Second Lake Pontchartrain Causeway in Louisiana, U.S.
39 km – undersea portion of the Channel tunnel
53.9 km – length of the Seikan Tunnel,, the longest rail tunnel in the world
77 km – rough total length of the Panama Canal

Geographical

10 km – height of Mauna Kea in Hawaii, measured from its base on the ocean floor
11 km – deepest-known point of the ocean, Challenger Deep in the Mariana Trench
11 km – average height of the troposphere
14 km – width of the Strait of Gibraltar
21 km – length of Manhattan
22 km – narrowest width of the Cook Strait between New Zealand's main islands
23 km – depth of the 1931 [Dogger Bank earthquake|largest earthquake ever recorded in the United Kingdom], in 1931 at the Dogger Bank of the North Sea
34 km – narrowest width of the English Channel at the Strait of Dover
50 km – approximate height of the stratosphere
90 km – width of the Bering Strait

Astronomical

10 km – diameter of the most massive neutron stars
13 km – mean diameter of Deimos, the smaller moon of Mars
20 km – diameter of the least massive neutron stars
20 km – diameter of Leda, one of Jupiter's moons
20 km – diameter of Pan, one of Saturn's moons
22 km – diameter of Phobos, the larger moon of Mars
27 km – height of Olympus Mons above the Mars reference level, the highest-known mountain of the Solar System
30.8568 km – 1 picoparsec
43 km – diameter difference of Earth's equatorial bulge
66 km – diameter of Naiad, the innermost of Neptune's moons

100 kilometres

A length of 100 kilometres, as a rough amount, is relatively common in measurements on Earth and for some astronomical objects.
It is the altitude at which the FAI defines spaceflight to begin.
To help compare orders of magnitude, this section lists lengths between 100 and 1,000 kilometres.

Conversions

A distance of 100 kilometres is equal to about 62 miles.

Human-defined scales and structures

100 km – the Karman line: the internationally recognized boundary of outer space
105 km – distance from Giridih to Bokaro
109 km – length of High Speed 1 between London and the Channel Tunnel
130 km – range of a Scud-A missile
163 km – length of the Suez Canal
164 km – length of the Danyang–Kunshan Grand Bridge
213 km – length of Paris Métro
217 km – length of the Grand Union Canal
223 km – length of the Madrid Metro
300 km – range of a Scud-B missile
386 km – altitude of the International Space Station
408 km – length of the London Underground
460 km – distance from London to Paris
470 km – distance from Dublin to London as the crow flies
600 km – range of a Scud-C missile
600 km – height above ground of the Hubble Space Telescope
804.67 km – distance of the Indy 500 automobile race

Geographical

42 km – width of Singapore
75 km – width of Rhode Island
111 km – distance covered by one degree of latitude on Earth's surface
120 km – width of Brunei
180 km – distance between Mumbai and Nashik
200 km – width of Qatar
203 km – length of Sognefjorden, the third-largest fjord in the world
220 km – distance between Pune and Nashik
240 km – width of Rwanda
240 km – widest width of the English Channel
400 km – width of West Virginia
430 km – length of the Pyrenees
450 km – length of the Grand Canyon
500 km – widest width of Sweden from east to west
501 km – width of Uganda
550 km – distance from San Francisco to Los Angeles as the crow flies
560 km – distance of Bordeaux–Paris, formerly the longest one-day professional cycling race
590 km – length of land boundary between Finland and Sweden
724 km – length of the Om River
800 km – width of Germany
871 km – distance from Sydney to Melbourne
897 km – length of the River Douro
900 km – distance from Berlin to Stockholm
956 km – distance from Washington, D.C., to Chicago, Illinois, as the crow flies
970 km – distance from Land's End to John o' Groats as the crow flies

Astronomical

100 km – the altitude at which the FAI defines spaceflight to begin
167 km – diameter of Amalthea, one of Jupiter's inner moons
200 km – width of Valles Marineris
220 km – diameter of Phoebe, the largest of Saturn's outer moons
300 km – the approximate distance travelled by light in one millisecond
340 km – diameter of Nereid, the third-largest moon of Neptune which has a highly elliptical orbit
350 km – lower bound of Low Earth orbit
420 km – diameter of Proteus, the second-largest moon of Neptune
468 km – diameter of the asteroid 4 Vesta
472 km – diameter of Miranda, one of Uranus's major moons
974.6 km – greatest diameter of 1 Ceres, the largest Solar System asteroid

1 megametre

The is a unit of length in the metric system equal to metres.
To help compare different orders of magnitude, this section lists lengths starting at 10⁶ m.

Conversions

1 megametre is equal to:

1000 km
approximately 621.37 miles

Human-defined scales and structures

2.100 Mm – length of proposed Iran-Pakistan-India gas pipe
2.100 Mm – distance from Casablanca to Rome
2.288 Mm – length of the official Alaska Highway when it was built in the 1940s
2.688 Mm – distance from Point Nemo, the farthest place anyone could get from any land, to the closest point of land, Easter Island
3.069 Mm – length of Interstate 95
3.846 Mm – length of U.S. Route 1
5.000 Mm – width of the United States
5.007 Mm – estimated length of Interstate 90
5.614 Mm – length of the Australian Dingo Fence
6.371 Mm – global-average Earth radius
6.4 Mm – length of the Great Wall of China
7.821 Mm – length of the Trans-Canada Highway, the world's longest national highway
8.836 Mm – road distance between Prudhoe Bay, Alaska, and Key West, Florida, the endpoints of the U.S. road network
8.852 Mm – aggregate length of the Great Wall of China, including trenches, hills and rivers
9.259 Mm – length of the Trans-Siberian Railway

Sports

The Munda Biddi Trail in Western Australia, Australia, is over 1,000 km long – the world's longest off-road cycle trail
1.200 Mm – the length of the Paris–Brest–Paris bicycling event
Several endurance auto races are, or were, run for 1,000 km:
*Bathurst 1000
*1000 km Brands Hatch
*1000 km Buenos Aires
*1000 km Donington
*1000 km Monza
*1000 km Nürburgring
*1000 km Silverstone
*1000 km Spa
*1000 km Suzuka
*1000 km Zeltweg

Geographical

1.010 Mm – distance from San Diego to El Paso as the crow flies
1.100 Mm – length of Italy
1.200 Mm – length of California
1.200 Mm – width of Texas
1.500 Mm – length of the Gobi Desert
1.600 Mm – length of the Namib, the oldest desert on Earth
2.000 Mm – distance from Beijing to Hong Kong as the crow flies
2.300 Mm – length of the Great Barrier Reef
2.800 Mm – narrowest width of Atlantic Ocean
2.850 Mm – length of the Danube river
2.205 Mm – length of Sweden's total land boundaries
2.515 Mm – length of Norway's total land boundaries
3.690 Mm – length of the Volga river, longest in Europe
4.000 Mm – length of the Kalahari Desert
4.350 Mm – length of the Yellow River
4.600 Mm – width of the Mediterranean Sea
4.800 Mm – length of the Sahara
4.800 Mm – widest width of Atlantic Ocean
5.100 Mm – distance from Dublin to New York as the crow flies
6.270 Mm – length of the Mississippi-Missouri River system
6.380 Mm – length of the Yangtze River
6.400 Mm – Length of the Amazon River
6.758 Mm – Length of the Nile system, longest on Earth
8.200 Mm – Approximate Distance from Dublin to San Francisco

Astronomical

1.000 Mm – estimated shortest axis of triaxial dwarf planet
1.186 Mm – diameter of Charon, the largest moon of Pluto
1.280 Mm – diameter of the trans-Neptunian object 50000 Quaoar
1.436 Mm – diameter of Iapetus, one of Saturn's major moons
1.578 Mm – diameter of Titania, the largest of Uranus's moons
1.960 Mm – estimated longest axis of Haumea
2.326 Mm – diameter of the dwarf planet Eris, the most massive trans-Neptunian object found to date
2.376 Mm – diameter of Pluto
2.707 Mm – diameter of Triton, largest moon of Neptune
3.122 Mm – diameter of Europa, the smallest Galilean satellite of Jupiter
3.476 Mm – diameter of Earth's Moon
3.643 Mm – diameter of Io, a moon of Jupiter
4.821 Mm – diameter of Callisto, a moon of Jupiter
4.879 Mm – diameter of Mercury
5.150 Mm – diameter of Titan, the largest moon of Saturn
5.262 Mm – diameter of Jupiter's moon Ganymede, the largest moon in the Solar System
6.371 Mm – radius of Earth
6.792 Mm – diameter of Mars

10 megametres

To help compare different orders of magnitude, this section lists lengths starting at 10⁷ metres.

Conversions

10 megametres is

6,215 miles
side of a square of area 100,000,000 square kilometres
radius of a circle of area 314,159,265 km²

Human-defined scales and structures

11.085 Mm – length of the Kyiv-Vladivostok railway, a longer variant of the Trans-Siberian Railway
13.300 Mm – length of roads rehabilitated and widened under the National Highway Development Project in India
39.000 Mm – length of the SEA-ME-WE 3 optical submarine telecommunications cable, joining 39 points between Norden, Germany, and Okinawa, Japan
53.800 Mm — length of the BNSF Railway
67.000 Mm – total length of National Highways in India
80.000 Mm – 20,000 leagues
100.000 Mm — height of a Space elevator

Geographical

10 Mm – approximate altitude of the outer boundary of the exosphere
10.001 Mm – length of the meridian arc from the North Pole to the Equator
40.000 Mm – length of the Ring of Fire
60.000 Mm – total length of the mid-ocean ridges

Astronomical

12.000 Mm — diameter of AR Scorpii, largest pulsar ever discovered
12.000 Mm – diameter of Sirius B, a white dwarf
12.104 Mm – diameter of Venus
12.742 Mm – diameter of Earth
12.900 Mm – minimum distance of the meteoroid from the centre of Earth on 31 March 2004, closest on record
14.000 Mm – smallest diameter of Jupiter's Great Red Spot
19.000 Mm – separation between Pluto and Charon
30.8568 Mm – 1 nanoparsec
34.770 Mm – minimum distance of the asteroid 99942 Apophis on 13 April 2029 from the centre of Earth
35.786 Mm – altitude of geostationary orbit
40.005 Mm – polar circumference of the Earth
40.077 Mm – equatorial circumference of the Earth
49.528 Mm – diameter of Neptune
51.118 Mm – diameter of Uranus

100 megametres

To help compare different orders of magnitude, this section lists lengths starting at 10⁸ metres.

102 Mm – diameter of HD 149026 b, an unusually dense Jovian planet
115 Mm – width of Saturn's Rings
120 Mm – diameter of EBLM J0555-57Ab, the smallest-known red dwarf
120 Mm – diameter of Saturn
142 Mm – diameter of Jupiter, the largest planet in the Solar System
170 Mm – diameter of TRAPPIST-1, a star discovered to have seven planets around it
174 Mm – diameter of OGLE-TR-122b, one of the smallest known stars
180 Mm – average distance covered during life
215 Mm – diameter of Proxima Centauri, the nearest star to the Solar System
257 Mm – diameter of TrES-4, one of the largest exoplanets
260 Mm – diameter of the Barnard's Star
272 Mm – diameter of WASP-12b
299.792 Mm – one light-second; the distance light travels in vacuum in one second
314 Mm – diameter of CT Cha b
384.4 Mm – average Earth–Moon distance
671 Mm – separation between Jupiter and Europa
696 Mm – radius of Sun
989 Mm – diameter of Epsilon Indi, one of the nearest stars to Earth

1 gigametre

The is a unit of length in the metric system equal to metres.
To help compare different distances this section lists lengths starting at 10⁹ metres.

1.2 Gm – separation between Saturn and Titan
1.39 Gm – diameter of Sun
1.5 Gm – orbit from Earth of the James Webb Space Telescope
1.71 Gm – diameter of Alpha Centauri A, one of the closest stars.
2.19 Gm – closest approach of Comet Lexell to Earth, happened on 1 July 1770; closest comet approach on record
2.38 Gm – diameter of Sirius A, brightest naked eye star.
3 Gm – total length of "wiring" in the human brain
3.5 Gm – diameter of Vega
4.2 Gm – diameter of Algol B
4.3 Gm – circumference of Sun
5.0 Gm – closest approach of Comet Halley to Earth, happened on 10 April 837
5.0 Gm – Size of the arms of the giant triangle shaped Michelson interferometre of the Laser Interferometre Space Antenna planned to start observations sometime in the 2030s.
7.9 Gm – diameter of Gamma Orionis, a blue dwarf or blue giant
9.0 Gm – estimated diameter of the event horizon of Sagittarius A*, the supermassive black hole in the center of the Milky Way galaxy

10 gigametres

To help compare different distances this section lists lengths starting at 10¹⁰ metres.

10.4 Gm – diameter of Spica, an oval-shaped blue giant star and a List of [supernova candidates|nearby supernova candidate].
12.6 Gm – diameter of Pollux, the closest red giant star to the Sun. It is a red clump star fusing helium into carbon at its core.
15 Gm – closest distance of Comet Hyakutake from Earth
18 Gm – one light-minute
24 Gm – radius of a heliostationary orbit
30.8568 Gm – 1 microparsec
35 Gm – approximate diameter of Arcturus, a close red giant star. It is on the red giant branch, fusing hydrogen into helium in a shell surrounding an inert helium core.
46 Gm – perihelion distance of Mercury
55 Gm – 60,000-year perigee of Mars
58 Gm – average passing distance between Earth and Mars at the moment they overtake each other in their orbits
61 Gm – diameter of Aldebaran, a red giant branch star
70 Gm – aphelion distance of Mercury
76 Gm – Neso's apocentric distance; greatest distance of a natural satellite from its parent planet

100 gigametres

To help compare distances at different orders of magnitude this section lists lengths starting at 10¹¹ metres.

103 Gm – diameter of Rigel
109 Gm – distance between Venus and the Sun
149.6 Gm – average distance between the Earth and the Sun – the original definition of the astronomical unit
163 Gm – diameter of Deneb, a blue supergiant
228 Gm – distance between Mars and the Sun
255 Gm – diameter of Enif, a small red supergiant star in the constellation Pegasus
511 Gm – average diameter of Mira, a pulsating red giant and the progenitor of the Mira variables. It is an asymptotic giant branch star.
570 Gm – length of the tail of Comet Hyakutake measured by Ulysses; the actual value could be much higher
590 Gm – diameter of the Pistol Star, a blue hypergiant star
591 Gm – minimum distance between the Earth and Jupiter
780 Gm – average distance between Jupiter and the Sun
785 Gm – diameter of Rho Cassiopeiae, a rare yellow hypergiant star
947 Gm – diameter of Antares A
965 Gm – maximum distance between the Earth and Jupiter

1 terametre

The is a unit of length in the metric system equal to metres.
To help compare different distances, this section lists lengths starting at 10¹² m.

≈1 [|Tm] – 6.7 au – diameter of the red supergiant Betelgeuse based on multiple angular diameter estimates
1.032 Tm – 6.9 au – diameter of the blue hypergiant Eta Carinae
1.079 Tm – 7.2 au – one light-hour
1.114 Tm – 7.5 au – diameter of WOH G64, a star in the Large Magellanic Cloud, which recently transformed from a red hypergiant to a yellow hypergiant
1.4 Tm – 9.5 au – average distance between Saturn and the Sun
1.47 Tm – 9.9 au – diameter of HR 5171 A, a yellow hypergiant star.
1.5 Tm – 10 au – estimated diameter of VV Cephei A, a red hypergiant with a blue dwarf companion.
1.75 Tm – 11.7 au – estimated diameter of Mu Cephei, a red supergiant among the largest-known stars.
2 Tm – 13.2 au – estimated diameter of VY Canis Majoris, a red hypergiant that is among the largest-known stars
2.142 Tm – 14.3 au – estimated diameter of WOH G64, prior to its transformation into a yellow hypergiant.
2.9 Tm – 19.4 au – average distance between Uranus and the Sun
4.4 Tm – 29.4 au – perihelion distance of Pluto
4.5 Tm – 30.1 au – average distance between Neptune and the Sun
4.5 Tm – 30.1 au – inner radius of the Kuiper belt
5.7 Tm – 38.1 au – perihelion distance of Eris
6.0 Tm – 40.5 au – distance from Earth at which the Pale Blue Dot photograph was taken.
7.3 Tm – 48.8 au – aphelion distance of Pluto
7.5 Tm – 50.1 au – outer boundary of the Kuiper Belt

10 terametres

To help compare different distances this section lists lengths starting at 10¹³ m.

10 Tm – 67 AU – diameter of a hypothetical quasi-star
11.1 Tm – 74.2 AU – distance that Voyager 1 began detecting returning particles from termination shock
11.4 Tm – 76.2 AU – perihelion distance of 90377 Sedna
12.1 Tm – 70 to 90 AU – distance to termination shock
12.9 Tm – 86.3 AU – distance to 90377 Sedna in March 2014
13.2 Tm – 88.6 AU – distance to Pioneer 11 in March 2014
14.1 Tm – 94.3 AU – estimated radius of the Solar System
14.4 Tm – 96.4 AU – distance to Eris in March 2014
15.1 Tm – 101 AU – distance to heliosheath
16.5 Tm – 111 AU – distance to Pioneer 10 as of March 2014
16.6 Tm – 111.2 AU – distance to Voyager 2 as of May 2016
18 Tm – 123.5 AU – distance between the Sun to the farthest dwarf planet in the Solar System, the Farout 2018 VG18
19.5 Tm – 132.7 AU – distance between the Sun to one of the farthest known objects in the solar system, 2018 AG37
20.0 Tm – 135 AU – distance to Voyager 1 as of May 2016
20.6 Tm – 138 AU – distance to Voyager 1 as of late February 2017
21 Tm – 140 AU – distance to Voyager 2 as of August 2025
21.1 Tm – 141 AU – distance to Voyager 1 as of November 2017
25.1 Tm – 168 AU – distance to Voyager 1 as of August 2025
25.9 Tm – 173 AU – one light-day
30.8568 Tm – 206.3 AU – 1 milliparsec
55.7 Tm – 371 AU – aphelion distance of the comet Hale-Bopp

100 terametres

To help compare different distances this section lists lengths starting at 10¹⁴ m.

140 Tm – 937 AU – aphelion distance of 90377 Sedna
172 Tm – 1150 AU – Schwarzschild diameter of H1821+643, one of the most massive black holes known
181 Tm – 1210 AU – one light-week
308.568 Tm – 2063 AU – 1 centiparsec
757 Tm – 5059 AU – radius of the Stingray Nebula
777 Tm – 5180 AU – one light-month

1 petametre

The is a unit of length in the metric system equal to 10¹⁵ metres.
To help compare different distances this section lists lengths starting at 10¹⁵ m.

1.0 [|Pm] = 0.105702341 light-years
1.9 Pm ± 0.5 Pm = 12,000 AU = 0.2 light-year radius of Cat's Eye Nebula's inner core
3.08568 Pm = 20,626 AU = 1 deciparsec
4.7 Pm = 30,000 AU = half-light-year diameter of Bok globule Barnard 68
7.5 Pm – 50,000 AU – possible outer boundary of Oort cloud
9.5 Pm – 63,241.1 AU – one light-year, the distance light travels in one year
9.9 Pm – 66,000 AU – aphelion distance of the C/1999 F1 (Catalina)

10 petametres

To help compare different distances this section lists lengths starting at 10¹⁶ m.

15 Pm – 1.59 light-years – possible outer radius of Oort cloud
20 Pm – 2.11 light-years – maximum extent of influence of the Sun's gravitational field
30.9 Pm – 3.26 light-years – 1 parsec
39.9 Pm – 4.22 light-years – distance to Proxima Centauri
81.3 Pm – 8.59 light-years – distance to Sirius
94.6 Pm – 1 light-decade

100 petametres

To help compare different distances this section lists lengths between 10¹⁷ m and 10¹⁸ m.

110 Pm – 12 light-years – Distance to Tau Ceti
230 Pm – 24 light-years – diameter of the Orion Nebula
240 Pm – 25 light-years – Distance to Vega
260 Pm – 27 light-years – Distance to Chara, a star approximately as bright as the Sun. Its faintness gives an idea how the Sun would appear when viewed from this distance.
308.568 Tm – 32.6 light-years – 1 dekaparsec
350 Pm – 37 light-years – distance to Arcturus
373.1 Pm – 39.44 light-years – distance to TRAPPIST-1, a star recently discovered to have 7 planets around it
400 Pm – 42 light-years – distance to Capella
620 Pm – 65 light-years – distance to Aldebaran
750 Pm – 79.36 light-years – distance to Regulus
900 Pm – 92.73 light-years – distance to Algol
946 Pm – 1 light-century

1 exametre

The is a unit of length in the metric system equal to 10¹⁸ metres. To help compare different distances this section lists lengths between 10¹⁸ m and 10¹⁹ m.

1.2 Em – 129 light-years – diameter of Messier 13
1.6 Em – 172 ± 12.5 light-years – diameter of Omega Centauri
3.08568 Em – 326.1 light-years – 1 hectoparsec
3.1 Em – 310 light-years – distance to Canopus according to Hipparcos
3.9 Em – 410 light-years – distance to Betelgeuse according to Hipparcos
6.2 Em – 650 light-years – distance to the Helix Nebula, located in the constellation Aquarius
8.2 Em – 860 light-years – distance to Rigel according to Hipparcos
9.4 Em — 1 light-millennium – 1000 light-years

10 exametres

To help compare different orders of magnitude, this section lists distances starting at 10 Em.

10.6 Em – 1,120 light-years – distance to WASP-96b
13 Em – 1,300 light-years – distance to the Orion Nebula
14 Em – 1,500 light-years – approximate thickness of the plane of the Milky Way galaxy at the Sun's location
14.2 Em – 1,520 light-years – diameter of the NGC 604
30.8568 Em – 3,261.6 light-years – 1 kiloparsec
31 Em – 3,200 light-years – distance to Deneb according to Hipparcos
46 Em – 4,900 light-years – distance to OGLE-TR-56, the first extrasolar planet discovered using the transit method
47 Em – 5,000 light-years – distance to the Boomerang Nebula, coldest place known
53 Em – 5,600 light-years – distance to the globular cluster M4 and the extrasolar planet PSR B1620-26 b within it
61 Em – 6,500 light-years – distance to Perseus Spiral Arm
71 Em – 7,500 light-years – distance to Eta Carinae
94.6073 Em – 1 light-decamillennium = 10,000 light-years

100 exametres

To help compare different orders of magnitude, this section lists distances starting at 100 Em.

150 Em – 16,000 light-years – diameter of the Small Magellanic Cloud, a dwarf galaxy orbiting the Milky Way
200 Em – 21,500 light-years – distance to OGLE-2005-BLG-390Lb
240 Em – 25,000 light-years – distance to the Canis Major Dwarf Galaxy
260 Em – 28,000 light-years – distance to the center of the Galaxy
400 Em – 48,000 light years – diameter of the Fireworks Galaxy
830 Em – 88,000 light-years – distance to the Sagittarius Dwarf Elliptical Galaxy
946 Em – 1 light-centum-millennium = 100,000 light-years

1 zettametre

The is a unit of length in the metric system equal to 10²¹ metres.
To help compare different orders of magnitude, this section lists distances starting at 1 Zm.

1.7 Zm – 179,000 light-years – distance to the Large Magellanic Cloud, largest satellite galaxy of the Milky Way
<1.9 Zm – <200,000 light-years – revised estimated diameter of the disc of the Milky Way Galaxy. The size was previously thought to be half of this.
2.0 Zm – 210,000 light-years – distance to the Small Magellanic Cloud
2.8 Zm – 300,000 light-years – distance to the Intergalactic Wanderer, one of the most distant globular clusters of Milky Way
8.5 Zm – 900,000 light-years – distance to the Leo I Dwarf Galaxy, farthest-known Milky Way satellite galaxy
9.5 Zm – 1 light-megaannum = 1,000,000 light-years

10 zettametres

To help compare different orders of magnitude, this section lists distances starting at 10 Zm.

24 Zm – 2.5 million light-years – distance to the Andromeda Galaxy, the nearest major galaxy.
30.8568 Zm – 3.2616 million light-years – 1 megaparsec
40 Zm – 4.2 million light-years – distance to the IC 10, a distant member of the Local Group of galaxies
49.2 Zm – 5.2 million light-years – width of the Local Group of galaxies
95 Zm – 10 million light-years – distance to the Sculptor Galaxy in the Sculptor Group of galaxies
95 Zm – 10 million light-years – distance to the Maffei 1, the nearest giant elliptical galaxy in the Maffei 1 Group

100 zettametres

To help compare different orders of magnitude, this section lists distances starting at 100 Zm.

140 Zm – 15 million light-years – distance to Centaurus A galaxy
250 Zm – 27 million light-years – distance to the Pinwheel Galaxy
280 Zm – 30 million light-years – distance to the Sombrero Galaxy
570 Zm – 60 million light-years – approximate distance to the Virgo Cluster, nearest galaxy cluster
620 Zm – 65 million light-years – approximate distance to the Fornax Cluster
800 Zm – 85 million light-years – approximate distance to the Eridanus Cluster

1 yottametre

The is a unit of length in the metric system equal to 10²⁴ metres.
To help compare different orders of magnitude, this section lists distances starting at 1 Ym.

1.2 Ym – 127 million light-years – distance to the closest observed gamma ray burst GRB 980425
1.3 Ym – 137 million light-years – distance to the Centaurus Cluster of galaxies, the nearest large supercluster
1.9 Ym – 201 million light-years – diameter of the Local Supercluster
2.17 Ym – 1 light-galactic-years – 230 million light-years
2.3 Ym – 225 to 250 million light-years – distance light travels in vacuum in one galactic year
2.8 Ym – 296 million light-years – distance to the Coma Cluster
3.15 Ym – 330 million light years – diameter of the Boötes Void
3.2 Ym – 338 million light-years – distance to Stephan's Quintet
4.7 Ym – 496 million light-years – length of the CfA2 Great Wall, one of the largest observed superstructures in the Universe
6.1 Ym – 645 million light-years – distance to the Shapley Supercluster
9.5 Ym – 996 million light-years – diameter of the Eridanus Supervoid

10 yottametres

To help compare different orders of magnitude, this section lists distances starting at 10 Ym. At this scale, expansion of the universe becomes significant. Distance of these objects are derived from their measured redshifts, which depends on the cosmological models used.

13 Ym – 1.37 billion light-years – length of the South Pole Wall
13 Ym – 1.38 billion light-years – length of the Sloan Great Wall
18 Ym – redshift 0.16 – 1.9 billion light-years – distance to the quasar 3C 273
30.8568 Ym – 3.2616 billion light-years – 1 gigaparsec
31.2204106 Ym − 3.3 billion light-years − length of The Giant Arc, a large cosmic structure discovered in 2021
33 Ym – 3.5 billion light-years – maximum distance of the Galaxy Redshift Survey">Milky Way">Galaxy Redshift Survey
37.8 Ym – 4 billion light-years – length of the Huge-LQG
75 Ym – redshift 0.95 – 8 billion light-years – approximate distance to the supernova SN 2002dd in the Hubble Deep Field North
85 Ym – redshift 1.6 – 9 billion light-years – approximate distance to the gamma-ray burst GRB 990123
94.6 Ym – 10 billion light-years – approximate distance to quasar OQ172
94.6 Ym – 10 billion light-years – length of the Hercules–Corona Borealis Great Wall, one of the largest and most massive-known cosmic structures known

100 yottametres

To help compare different orders of magnitude, this section lists distances starting at 100 Ym. At this scale, expansion of the universe becomes significant. Distance of these objects are derived from their measured redshifts, which depend on the cosmological models used.

124 Ym – redshift 7.54 – 13.1 billion light-years – light travel distance to the quasar ULAS J1342+0928, the most distant-known quasar as of 2017
130 Ym – redshift 1,000 – 13.8 billion light-years – distance to the source of the cosmic microwave background radiation; radius of the observable universe measured as a LTD
260 Ym – 27.4 billion light-years – diameter of the observable universe
440 Ym – 46 billion light-years – radius of the universe measured as a comoving distance
590 Ym – 62 billion light-years – cosmological event horizon: the largest comoving distance from which light will ever reach us at any time in the future
886.48 Ym – 93.7 billion light-years – the diameter of the observable universe ; however, there might be unobserved distances that are even greater.

1 ronnametre

The is a unit of length in the metric system equal to 10²⁷ metres.
To help compare different orders of magnitude, this section lists distances starting at 1 Rm. At this scale, expansion of the universe becomes significant. Distance of these objects are derived from their measured redshifts, which depend on the cosmological models used.

>1 Rm – >105.7 billion light-years – size of universe beyond the cosmic light horizon, depending on its curvature; if the curvature is zero, the value can be infinite as previously mentioned.
2.764 Rm - 292.2 billion light-years – circumference of the observable universe, as it is in the shape of a sphere.

Upper limits

≈10^{10^10¹²²}light-years – the possible size of the universe after cosmological inflation.
≈∞ light-years – theoretical size of the multiverse if it exists.
≈∞+ light-years - theoretical size of the omniverse if it exists, with all universes combined to an infinite amount of multiverses.