How Sanskrit Calendar Months Work

A month is a moon cycle, not a fixed block

A Gregorian month is an arbitrary fixed length — 28 to 31 days, unrelated to anything in the sky. A Sanskrit month (Masa) is tied directly to the Moon's cycle: roughly 29.5 days, new moon to new moon. This single difference is the root of everything else on this page.

Two ways to draw the boundary: Amanta vs Purnimanta

Regional traditions disagree on where exactly a month starts and ends:

• Amanta ("ending at Amavasya") — the month runs new-moon to new-moon. Used across South India, Maharashtra, and Gujarat.
• Purnimanta ("ending at Purnima") — the month runs full-moon to full-moon. Traditionally used across much of North India.

Both systems use the same 12 month names and agree on which lunar fortnight (Paksha) falls in which month for most of the month — they differ only in exactly where the boundary falls, which shifts the first or second half of a month's name by about two weeks depending on convention. This site uses the Amanta convention throughout.

Why a Sanskrit month never matches a Gregorian month

Because a Sanskrit month starts wherever the previous new moon happened to fall, it almost never aligns with the 1st of a Gregorian month. In practice, this means most Gregorian months contain the tail end of one Sanskrit month and the beginning of the next. For example, in 2027, January runs from the last few days of Pausha straight into most of Magha:

See the full year breakdown for 2027 for every month's exact transition.

Keeping the seasons in step: Adhik Masa

12 lunar months add up to about 354 days — 11 days short of the 365-day solar year. Left alone, this drift would push festivals steadily earlier through the seasons over a human lifetime, the way it does in the purely lunar Islamic calendar. The Sanskrit calendar avoids this with Adhik Masa ("extra month") — roughly every 32–33 months, a 13th lunar month is inserted, resetting the drift and keeping month names anchored to roughly the same season year after year. See our full Adhik Masa explainer for exactly how the calendar decides which month becomes the extra one.

The rarer opposite case: Kshaya Masa

Far less commonly, the calendar can lose a month rather than gain one — called Kshaya Masa ("diminished month"). This happens when a single lunar month contains two Sankranti (solar transits) instead of the usual one, meaning that lunar cycle doesn't get its own distinct month name and is effectively absorbed into the surrounding months. Because it requires a very specific alignment between the lunar and solar cycles, Kshaya Masa is dramatically rarer than Adhik Masa — occurring roughly once every 19 years at most, and skipping many 19-year windows entirely. When it does happen, it's always accompanied by two Adhik Masa occurring close together in the same broader period, keeping the long-run balance between lunar and solar time intact.

The 12 names, and what they're named after

Each month takes its name from the Nakshatra (lunar mansion) the Moon was traditionally full in during that month — a naming convention dating to the Vedic period. See the full reference list for all 12 names, their Devanagari, and which festivals fall in each, or our Hindu Calendar Months guide for the same 12 months with live current-month highlighting.