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This is a site all about calendars - historical ones, new ones, and discussions about them: for the scientist, astronomer and the calendar enthusiast. To write a new Calendar Wiki article, enter the page title in the box below. You should read the guidelines for contributors before creating an article. If you are new to wikis, you may want to try the tutorial on the Central Wikia. There is also a list of all help pages.

Featured Calendar

The International Standard Calendar is the subset of the International Calendar which is recognised by the International Standardisation Organisation in ISO 8601, parts 1 and 2. It builds upon the primary International Standard Month Calendar, which defines a year based on months and uses the (proleptic) Gregorian leap day rule for a 400-year leap cycle. The alternative International Standard Day Calendar just places the leap day at the end of the year. The secondary International Standard Week Calendar uses the same year count but subdivides a year into 52 weeks and occasionally a 53rd one. The International Calendar contains more notation variants and auxiliary calendars, such as quarters, full-week months, seasons, shifts and placeholders.

Where to start

What is a calendar? Stop by our general article to find out. Here are some good places to start learning about calendars: Current calendars Historic calendars Proposed calendars Calendar reform (proposed reforms to the Gregorian calendar) Prospects of such reform Software

User blogs

Latest: Crissov • 4 May 2023 1 Possible dates for a fixed Easter The date of Easter and its lunisolar computation Computus is of central importance to many Christian churches. It is historically linked to the Jewish holiday of Pessach, Passa or Passover, which begins th… Read Full Post Arivumani1 • 30 March 2020 1 New Weekdays for Perpetual Calendars Today we are using Classical planets, Sun, Moon, Mars, Mercury, Jupiter, Venus and Saturn as weekdays Sunday, Monday, Tuesday, Wednesday, Thursday, Friday and Saturday respectively. Modern planets U… Read Full Post Loco123456 • 10 March 2019 1 Thomas and the Magic Railroad - The Lost Edition Petitoin: Please Sign Hello everybody, A nonprofit organization called "Restore the Magic" needs help in getting 10,000 signatures on their petition. The petition is to help get the director's cut of "Thomas and the Magic … Read Full Post See more >