Concept of Adhikmas and Kshaymas in Hindu Calender

The twelve Hindu months (māsa) are equal to approximate 356 days, while solar year have 365 or 366 (in leap year) which create difference of 9 to 10 days, which is offset every 3rd year. Thus, the Hindu lunar calendar adds one extra month every third year. This extra month is known by various names; adhik mass, mal mass, purushottam mass, malimmacha.

It is the thirteenth month of the lunar calendar. As per the lunar month, when the sun does not at all transit into any rāśi but simply keeps moving within a rāśi in a lunar month (i.e. before a new moon), then that lunar month will be named according to the first upcoming transit. It will also take the epithet of adhika or “extra”.

• For example, if a lunar month elapsed without a solar transit and the next transit is into Meṣa, then this month without transit is labeled Adhika Chaitra Māsa. This Extra Month, or adhika māsa falls every 32.5 months. It is also known as puruśottama māsa, so as to give it a devotional name.
• Please note that there are no adhika māsa falling during Kārtika to Māgh.
• Please also note that just as there is the lunar year with the extra month (adhik mass), so it there a lunar year with a diminished or reduced month, with only eleven months only is very rare indeed. It occurs once in 140 years or once in 190 years.

Kshaya Masa or Lost Month

If the sun transits into two rāshis within a lunar month, then the month will have to be labeled by both transits and will take the epithet kṣaya or “loss”. There is considered to be a “loss” because in this case, there is only one month labeled by both transits. If the sun had transited into only one raashi in a lunar month as is usual, there would have been two separate months labeled by the two transits in question.

For example, if the sun transits into Meṣa and Vṛṣabha in a lunar month, then it will be called Chaitra-Vaiśākha kṣaya-māsa. There will be no separate months labeled Chaitra and Vaiśākha. A Kṣaya-Māsa occurs very rarely.