How Hindu Festival Dates Are Calculated

Hindu festival dates can look confusing if you expect every festival to fall on the same Gregorian date each year. The reason is simple: many observances follow the Hindu lunar or solar calendar rather than the civil calendar.

HinduLab combines several date rules to build the annual festival calendar.

Tithi-Based Festivals

Many festivals are tied to a specific tithi, paksha, and lunar month. For example, Janmashtami is associated with Krishna Paksha Ashtami in Bhadrapada, while many Purnima and Amavasya observances depend on the full moon or new moon day of a particular lunar month.

Vrat-Derived Dates

Ekadashi, Pradosham, Sankashti Chaturthi, Purnima, Amavasya, and Masik Shivaratri are recurring vrats. HinduLab computes these occurrences and then maps well-known observances where relevant.

Solar Festivals

Sankranti festivals follow the Sun's transition into a sidereal rashi. Makar Sankranti is the best-known example and usually falls around January 14 or 15.

Regional and Family Practice

Some festivals are observed differently by region, sampradaya, or family tradition. A date can be widely shared while ritual timing still depends on local sunrise, sunset, or tithi boundaries.

Useful HinduLab tools:

• Festival Calendar
• Calculation Methodology
• Monthly Panchang
• Today's Panchang