Paksha
Paksha refers to a fortnight period consisting of various lunar phases in a month of the Hindu lunar calendar. Literally meaning "side" in Sanskrit, it refers to the periods between amavasya and purnima, and vice versa.
A lunar month in the Hindu calendar has two fortnights, with each fortnight subdivided into lunar days called tithis. A paksha consists of 15 such tithis, each of which correspond to a 12-degree angular motion of the Moon. The fortnight between amavasya and purnima is called as Shukla Paksha or Gaura Paksha, which corresponds to the period of the waning moon. The second fortnight is called Krishna Paksha or Vadhya Paksha' and corresponds to the period of the waxing moon. Amavasya corresponds to the period when the Moon is within 12 degrees of angular distance from the Sun before their conjunction.
A lunar month begins on the next day after amavasya in the amanta tradition and on the next day after purnima in the purnimanta system. The amanta system is followed majorly in the South India and the purnimanta system in North India.
Shukla Paksha
Shukla Paksha refers to the bright lunar fortnight in the Hindu calendar, corresponding to the waning moon. Shukla is the Sanskrit word for "white" or "bright". The Shukla Paksha is a period of 15 days, which begins after the amavasya and culminating on purnima and is considered auspicious.Numerous festivals are held during this period, including the Navaratri festivals, most importantly Chaitra Navaratri and Ashvin Navaratri.
| Day | Tithi | Festival | Month |
| 1st day | Pratipada | Gudi Padwa, Ugadi | Chaitra |
| 1st day | Pratipada | Bali Pratipada, Govardhan Puja | Kartika |
| 2nd day | Dvitiya | Bhaibeej | Kartika |
| 3rd day | Tritiya | Teej | Bhadrapada |
| 3rd day | Tritiya | Akshaya Tritiya | Vaishakha |
| 4th day | Chaturthi | Ganesh Chaturthi | Bhadrapada |
| 4th day | Chaturthi | Ganesh Jayanti | Magha |
| 5th day | Panchami | Nuakhai | Bhadrapada |
| 5th day | Panchami | Vivaha Panchami | Margashirsha |
| 5th day | Panchami | Vasanta Panchami | Magha |
| 6th day | Shasthi | Sitalsasthi | Jyestha |
| 8th day | Ashtami | Radhashtami | Bhadrapada |
| 9th day | Navami | Rama Navami | Chaitra |
| 10th day | Dashami | Vijayadashami | Ashvin |
| 11th day | Ekadashi | Shayani Ekadashi | Ashadha |
| 11th day | Ekadashi | Vaikuntha Ekadashi | Margashirsha |
| 14th day | Chaturdashi | Samvatsari | Bhadrapada |
| 15th day | Purnima | Guru Purnima | Ashada |
Krishna Paksha
Krishna Paksha refers to the dark lunar fortnight in the Hindu calendar, corresponding to the waxing moon. Krishna means "dark" in Sanskrit. Krishna Paksha is a period of 15 days, which begins after the purnima day, and ends on the amavasya day. The period is considered inauspicious, as the moon loses light during this period.Festivals during the Krishna Paksha are:
| Day | Tithi | Festival | Month |
| 4th day | Chaturthi | Karva Chauth | Kartika |
| 8th day | Ashtami | Krishna Janmashtami | Śrāvaṇa |
| 13th day | Thrayodashi | Dhanteras | Kartika |
| 13th day | Thrayodashi | Pradosha | Magha |
| 14th day | Chaturdashi | Maha Shivaratri | Magha |
| 14th day | Chaturdashi | Naraka Chaturdashi | Kartika |
| 15th day | Amavasya | Lakshmi Puja | Kartika |