Ahargana is defined as the no of days elapsed after the start of the Iron Age, the Kali Yuga, which began on 3102 BC.
Kali Era = English Era +3102
The no of days elapsed from Kali Start was 1822903 on 01/01/1890.
Hence
Ahargana = ( xdate – 01/01/1980 ) + 1822903
where xdate is the date of birth.
This Ahargana is printed on every V A Horoscope. All calculations in Indian Astronomy is based on Ahargana. Ahas means day in Sanskrit and gana means calculation.
The present Kali Era is therefore
3102 + 2010 = 5112
The difference between the Malayalam & English eras are 825. Malayalam Era is 1185 now and if you add 825 to Malayalam Era, you get English Era.