UTC Seconds Calculator

Calculate ‘UTC seconds’ (sometimes also called ‘epoch seconds’ or ‘unix seconds’) as the number of seconds since at 01-01-1970 00:00:00 for the GMT date/time provided. Will also allow you to enter UTC seconds or daynumber and compute the appropriate GMT date/time and yearday fields.


  1. If an invalid date such as Apr’31 is entered, UTCcalc will compute UTC seconds for May 1st. The select list fields are updated to reflect the correct representation of date/time.
  2. UTCcalc will not handle dates before 01-Jan-1987 00:00:00
  3. UTCcalc will not work with Netscape 3.x – (missing date.getUTCFullYear() function)

This is version: 2.4 16-Sep-2005

Month Day Year Hour Minute Seconds GMT

UTCseconds YearDay