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  Date Calculator, Version 2.6

Date and time calculations for genealogists

Date Calculator - Macintosh Software for Genealogists

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The Date Calculator is a MacOS X application for many date and time calculations useful to genealogists. It is free if you are a registered user of GEDitCOM II. For others you can get it at the Mac App store (coming soon) or you can click Buy Now below to order here.

The Date Calculator has the following capabilities and more:

Acknolwedgement: Date Calculator uses the date conversion utilities written by Scott E. Lee. He has written a Date Convertor Web Site that converts precise dates between Gregorian, Julian, and Hebrew calendars. He has also posted an excellent Calendar Overview about those calendars. Most of his overview is included (with permission) in the Date Calculator help.



If you are a registered user of GEDitCOM II the lastest version of Date Calculator is included in your download of GEDitCOM II. The first time you run it, enter your GEDitCOM II unlocking code and you are all set up.

For those not registered for GEDitCOM II, Date Calculator is available as a standalone app. To download Date Calculator, click a link in the following table. Most users should pick the lastest version (or the first line in the table). The others are Legacy downloads that are only needed if the first one does not work in your MacOS. The downloads are a 100% functional version, but will ask for an unlocking code every time it starts. Hopefully you will want to eliminate that message by purchasing a license and entering the code you will get.

Date Calculator Download Date Size (MB)
Date Calculator, version 2.6
Requires MacOS 10.10 (Yosemite) or newer; updated for Catalina (10.15). Choose this version first; use older versions below are only if problems arise or you have a system older than Yosemite.
31 May 2020 2.1
Date Calculator, version 2.1
Requires MacOS 10.9 (Mavericks)
12 JUN 2018 2.1
Date Calculator, version 2.0
Requires MacOS 10.4 (Tiger) through 10.8 (Mountain Lion)
7 JAN 2011 0.73


The Date Calculator is hopefully returning to the Mac AppStore soon. Meanwhile, or alternatively, and for those not registered for GEDitCOM II, you can purchase a standalone license for Date Calculator here using most credit cards or your PayPal account. To order here, click on the following "Buy Now" button and then:

  1. To pay by credit card, click the "Continue" link on the lower left of the invoice screen that appears.
  2. To pay using PayPal, use the log-in fields on the lower right.
Product Cost Buy
Date Calculator license
This license works for any version; get the version appropriate for your Mac from the above downloads table. Upgrading versions is free (use same license as before).

After completing your purchase, you will get a confirmation email from PayPal about the charge to your credit card or PayPal account. Your permanent code will arrive by email from (typically in 1-3 days). If you purchase and install from the Mac App store, it will be ready to run; you won't need to enter a code.


Author: John A. Nairn
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Other software by the same author: