Twelve lunar months add up to about 354 days, roughly 11 days short of the solar year. Left uncorrected, festivals would slide steadily through the seasons, as happens with purely lunar calendars. The Hindu lunisolar calendar solves this by occasionally inserting an extra month, the Adhik Maas, and, very rarely, dropping one, the Kshaya Maas.

The rule for an Adhik month

Each lunar month is named after the sidereal sign the Sun occupies at the new moon that starts it. Normally the Sun moves into a new sign (a Sankranti) once during every lunation, so each month gets a fresh name.

Because a solar month is slightly longer than a lunar month, sometimes no Sankranti falls between two consecutive new moons. That lunation is declared Adhik (extra). It takes the name of the following month, which is then called the Nija (regular) month. For example, an Adhik Shravana is followed by Nija Shravana. This happens roughly every 32 to 33 months.

The rule for a Kshaya month

When the Sun is moving fastest (around the Earth's closest approach to the Sun), a solar month can be shorter than a lunation. If the Sun passes through two signs within one lunation, one month name is skipped: that is a Kshaya month. It is very rare, and in such periods an Adhik month usually appears nearby in the same year, so the year still ends up with the right number of months overall.

Why it matters

These corrections keep the months tied to the seasons: Chaitra stays in spring, Shravana in the monsoon, Kartika in autumn. Festival rules that name a month (for example Shravana Purnima) then continue to land at the right time of year.

Traditional practice in Adhik Maas

Adhik Maas is also called Mal Maas and, in devotional tradition, Purushottam Maas, dedicated to Vishnu.

  • Traditionally, new auspicious beginnings such as marriages, griha pravesh and similar samskaras are avoided.
  • Devotional practices, such as japa, reading scripture, charity and vrat, are encouraged.
  • The two Ekadashis of the Adhik month have their own names: Padmini (Kamala) Ekadashi in the Shukla paksha and Parama Ekadashi in the Krishna paksha.

Most annual festivals are observed in the Nija month rather than the Adhik one. Traditions vary by region and Panchang convention.

On this platform

The engine checks the Sun's sidereal sign at both bounding new moons for every lunation and marks Adhik and Kshaya months automatically. See them on the calendar, and read Amanta and Purnimanta for how months are named.