Conversion between Gregorian date and Kali day number

Most of the popular calendar systems are not suitable for doing easy manipulation and arithmetic on date and time values. It has been recognized by scholars that a day count from a fixed epoch is the most convenient way to represent date and time. Astronomers use Julian Day Number, devised by John Herschel (who discovered the planet Uranus) in the 19th century. Many software libraries, including Microsoft's MFC, store date as the number of days since 1900 January 1 or some other date. Unix/Linux systems use the number of seconds since 1970 January 1.

Such a system has many uses:

  1. We can add or subtract a fixed time to date/time by adding the value directly.
  2. The difference between two dates/times can be found by finding subtracting the first number from the second.
  3. Weekday can be found from a single MOD operation.

Indians had this system a long back, at least since the 9th century. They represented the so-called Kali day number as the number of days elapsed since the Gregorian date January 23, -3101 (February 18, 3102 B.C.E. in Julian Calendar), the start of Kali yuga. Ancient Indian astronomical work use the Kali day number for representing dates and expressed astronomical results as its functions. South Indian mathematicians used to represent Kali day number using a language device called paralpperu.

You can convert a Gregorian date to Kali day number and back using the utilities below.


Gregorian date to Kali day

Kali day = 1869405 (Thursday)


Kali day to Gregorian date (Enter 0 for today's date)

Gregorian date = 2017 April 27 (Thursday)



Last modified: Fri Apr 21 14:51:59 PDT 2006 by Umesh
Maintained by: Umesh, Sindhu and Vishakh