MJD Calculator v4.2

Effortlessly convert Gregorian dates and times to and from Modified Julian Dates and times and unix dates and times.
Supports: Decimal and DVB standard MJD formats, millisecond and frame accuracy, 10 decimal place accuracy.

MJD Calculator is a simple, GUI based tool for converting between Gregorian (everyday) date and time format, Modified Julian Date and time, and unix date and time.

MJD Calculator runs on Win9x, Windows® ME, and Windows® NT.


The following feature list is taken from the detailed help file which is included with the programme.

  • Accurate over the DVB specified date range March 1st 1900 to February 28th 2100 for decimal display.
  • Accurate over the DVB format date range March 1st 1900 to April 22nd 2038 for DVB format.
  • Accurate over the unix date-time range 1st January 1970 to 19 January 2038 03:14:07.
  • MJD accurate to 10 decimal places.
  • Selectable time accuracy to the frame or the millisecond (decimal format).
  • Frames per second selectable between 25 and 30.
  • Copy and paste of MJD via windows clipboard (with automatic format recognition).
  • Calendar style selector for date.
  • Realtime updated current date, time, and MJD (decimal or DVB format selectable) or unix date-time.
  • Current time in local or UTC zone selectable.
  • System tray icon with current MJD (decimal, DVB, or Unix) tool-tip.
  • Can be run at startup as a background process displaying only the system tray icon.
  • Conversion of clipboard contents between MJD formats, and from MJD to gregorian (without using the GUI!)
  • Compact, simple to use GUI. (Is a help file really necessary?)


Supported OSes:
Windows 9x, ME, NT, XP, 7, 8, 10, 11.

Released: April 2001


MJD Calculator is Shareware. You may distribute (share) it freely, but of you continue to use it you must purchase a license.

Select License Option:

Please note that license purchases are processed manually so it may take a couple of days to get your code to you.


MJD Calculator’s UI