Calendar Calculator

Copyright © 1995-2018 Herb Weiner <>

The Calendar Calculator is 100 % web-based, and is therefore compatible with all versions of Windows, Mac, and Linux. It is compatible with most mobile platforms, although the results may not fit on screen withouut scrolling.

Use of the Calendar Calculator

Select a Locale and a Function, then click the Update button.

In most cases, the use of this Calendar Calculator is as simple as selecting the desired function, and clicking update. This calculator can display any month or year, or perform calculations (addition and subtraction) on dates.

For dates between October 4, 1582 and September 14, 1752, be sure to select the correct locale, since the Gregorian Calendar was adopted at different times in different locales.

Note that this Calendar Calculator is provided without any warranty, and should be used at your own risk. For more details, Information about the Calendar Calculator.

Select Locale

Italy, Portugal, Spain: October 15, 1582 follows October 4, 1582 (skip 10 days).

Great Britain, American Colonies: September 14, 1752 follows September 2, 1752 (skip 11 days).

France, Loraine: December 20, 1582 follows December 9, 1582 (skip 10 days).

Denmark, Flanders: January 5, 1583 follows December 25, 1582 (skip 10 days).

Select Function

The Calendar Calculator can perform any of the following functions:

Display Month

Display Entire Year

How many days between , and , ?

What day is , ?

What day is year(s), month(s), and day(s) , ?

Convert , from Calendar to Calendar.

When is the of closest to the year ?

What years close to use the same Calendar?

Get Printable (PDF) Perpetual Calendar

Display information about the Calendar Calculator and the Gregorian Calendar