Purushottam Maas or Adhik Maas is an extra month in the Hindu calendar that is inserted to keep the lunar and solar calendars aligned. Purushottam is an epithet of Vishnu, to whom the month is dedicated.

Generally, we know that there are 12 months in a Calendar year. Hindu calendar also has 12 months in a year, but each month is not of 30 or 31 days as we see in English Calendar.

This differentiation is because Hindu Calendar follow Moon’s Movement whereas English Calendar is made based on Sun’s Movement.

So as per Moon calendar, a month is exactly 29 days 10 hours and 48 minutes to sometimes 29 days 12 hours 44 minutes.

On an average a month stays for 29.5 days. 29.5 days multiplied by 12 months gives us the total days as 354 days.

The difference then between Lunar Calendar 354 days and Solar Calendar 365 days and 6 hours is 11 days 6 hours.

That difference must be corrected. Every third year this shortfall gets corrected as an extra month and that is called as Adhika Maasam.

Adhika Maasam comes in four combinations not exceeding three years.

1. 2 years and 4 months

2. 2 years and 9 months

3. 2 years and 10 months

4. 2 years and 11 months

In 2015, Adhik Mass was on 17th June to 16th July 2015 (This Adhika masa came in 2 years and 10 months)

In 2018, Adhik Mass was on 16th May to 13th June 2018 (This Adhika masa came in 2 years and 11 months)

In 2020, 17th Sept to 16th Oct 2020 (This Adhika masa came in 2 years and 4 months)

So,

Next Adhik Mass, will come In 2023, 17th June to 16th July 2023 (after 2 years and 9 months)