MJD Calculator
version 4.2
by Dan Gibson
Effortlessly convert Gregorian dates and times to and from Modified Julian Dates and times and unix dates and times.
Decimal and DVB standard MJD formats, millisecond and frame accuracy, 10 decimal place accuracy, simple GUI.

Features | Download | Register

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.
    Screen Shot 1
  • Accurate over the DVB specified date range March 1st 1900 to February 28th 2100 for decimal display. (See below)
  • Accurate over the DVB format date range March 1st 1900 to April 22nd 2038 for DVB format. (See below)
  • 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?)
You can download and use MJD Calculator for free. We'd like to know who is using downloading the software so please complete this short form, then click download.

    File size: 1,065Kb    File type: Zipped installer.
Name:     E-mail address:    
Privacy Note:
We only want to know who is downloading the software. Neither your name nor email address will be passed to any other person.

Alternatively, MJD Calculator is available from various software download sites, including
MJD Calculator is ShareWare. This means that you may distribute copies of MJD Calculator freely (so long as no charge is made for the software).
However, the software should be registered if you intend to keep it. The software is still fully functional without registration.
You should register MJD Calculator on-line. There are four different levels of registration.

Single User 10 user Corporate Distribution




Pay me securely with your Visa, MasterCard, Discover, or American Express card through PayPal!
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PayPal is our preferred method of payment as it is fast and secure. If you have a PayPal account, you can pay by clicking the 'Buy Now' buttons above.
If you don't have a PayPal account yet when you click the button above to pay, you will be guided through the simple steps to set up an account.
For alternative payment methods please email

For more information of the terms of each registration type, see the 'Registration' section of the MJD Calculator help file.
Registration payments are via PayPal.com and are secure. Your registration key will be sent on acceptance of your payment by GonMad.
Known bugs
Version 4.2 of MJD Calculator currently has no known bugs. Please e-mail software@gonmad.co.uk if you think you have found a bug.
If you have an interest in time and dates, you may also be interested in MultiClock, another small tool by the author of MJD Calculator.
MultiClock is a desktop clock for Windows® PCs which displays the time and date in more than a dozen different time and date formats including Julian Day, MJD, TJD, Unix, GPS, Swatch® internet @beats, and others. Multiclock can also act as an internet time client, synchronising itself (and your PC if you wish) with an internet time server.
MultiClock is available for download from the main
GonMad software page.

Last updated: November 2002 ©2001-2002 GonMad, No Original Thought, Dan Gibson.
All rights reserved.