List of ISBN registration groups

The registration group or identifier group is the second element in a 13-digit ISBN and indicates the country, geographic region, or language area where a book was published. The element ranges from one to five numerical digits.
In 2007, the length of an ISBN changed from 10 to 13 digits, and a new 3-digit prefix was added in front of 10-digit ISBNs. The following registration groups are compatible with or without a 978- prefix:

0–5
600–639
64–69
7
80–94
950–989
9900–9989
99900–99999

The following must have a 979- prefix:
*

through

Shorter registration group numbers are generally used for countries or regions with greater publishing volume. Because a longer number leaves room for fewer publishers and ISBNs, several countries have more than one number assigned. On the other hand, some countries have no unique number because they fall in a broader geographic region or language area.

With 10-digit ISBN or 978- prefix

Prefixes of length 1

Prefixes of length 2

Prefixes of length 3

Prefixes of length 4

Prefixes of length 5

Distribution

Length	Allocated	Unallocated	Unallocated list
1	7		-
2	16	5	64, 66~69
3	74	6	610, 635~639
4	84	6	9900~9905
5	97	3	99900, 99907, 99999
total	278	20

Countries by language area

Country

English
0

English
1

French
2

German
3

Australia

Countries in broader registration groups

; 5 former USSR
; 80 former
; 86 former
; 976
; 982 South Pacific

Countries with no exclusive registration group

; 18 countries

Countries with multiple registration groups

In parentheses, how many numbers are available.
Countries with over one million numbers are highlighted.
; Two
; Three
; Four
; Five

ISBN vs UN

; UN countries not part of ISBN
; ISBN agencies not part of the UN