Julian Date Calculator - CosmoWerx
$0.99 £0.59 0.79€

The Julian Date Calculator gives the user a simple and quick way to convert between Coordinated Universal Time (UTC) in the Gregorian Calendar to the Julian Date as well as the following selection of additional epochs and time systems:

  • Modified Julian Date
  • Reduced Julian Date
  • Truncated Julian Date (NIST and NASA)
  • Dublin Julian Day
  • Lilian Day Number
  • ANSI Date
  • Rata Die
  • Unix Time
  • RAMSES Time



The Julian date (JD) is the number of days and fractions of a day since noon January 1, 4713 BC at Greenwich. The Modified Julian Date (MJD) has an offset of 2,400,000.5 days from the Julian Date and hence starts at midnight November 17, 1858. The Julian Date is often used for scientific time measurement by the astronomy community and was introduced to provide a single system of dates that could be used when working with different calendars.