A Gregorian Calendar Reform

According to your computer, today is .

Versión en español


Every year, around September, I have to deal with the term planning for the subjects I teach. Each year is different. Not only week days for a given date change, but also different movable holidays do (mainly based on the Moon, being Easter the main example). All this makes such manual work be repeated once and again and from scratch.

The main goal of this web page is to reform the calendar, although, if I have to be more precise, it is more a task of renaming things with the purpose of making life a bit easier.

Disclaimer: Use at your own risk. Completely identical years may result, to say the least, boring. The author is not responsible of present or future damage (and, just in case, past damage as well) that these ideas may bring forth. [[End of my lawyer's cite]]

Features and goals:

  1. Main goal: the calendar must be the same for all years, so that plannings may be reused, for instance.
  2. The year must start and end following the natural cycle (at least in the zone of the Earth where our present calendar first appeared).
  3. Month, day, etc. calculations must be simplified wherever possible.
  4. Years and weeks must start on a holiday, so that we start on a good foot.


Year duration:

Reformed years last the same as Gregorian years: 365 days (366 days if a leap year).

Start of years:

It is pretty sad that years start in plain winter. It is more natural that they start in spring and die at the end of winter. Therefore, reformed years must start on the spring equinox (Nothern Hemisphere), more or less.

First year:

The first year of the new calendar is year 0, whose first day corresponds to the spring equinox of year 2000 AD, i.e. March 20, 2000 (at 7:35 UT, by the way).

Leap years:

Year x of the reformed calendar is a leap year if and only if Gregorian year x+2001 is a leap year.

Month duration:

All months have equal duration: 28 days, or exactly four weeks, except the last month of the year, Februaria, that has 29 days (30 days if it is a leap year). In exchange, that brings years of 13 months, but we can stand it, can't we?

Names of months:

The names of the 13 months of the year are, in this order: Marcha, Aprilia, Maya, Junia, Julia, Augusta, Septembra, Octobra, Novembra, Decembra, Undecembra, Januaria, and Februaria. Note that in Latin, seventh is septimus, and thus the seventh month is Septembra. The same goes for octavus and Octobra, etc. Names for the months and the days of the week in the reformed calendar end in -a since that suffix is used to form feminine names in Spanish and I want to dedicate this calendar to women.

Days of the month:

The first day of the month is day 0. The last day of the month is day 27, except for Februaria, that is 28 (or 29 if in a leap year).

Days of the week:

The week has seven days. The names of the days of the week are, in this order: Sundaya, Mondaya, Tuesdaya, Wednesdaya, Thursdaya, Fridaya, and Saturdaya. The first day of all months is Sundaya, as it is the first and last days of all years. The acute mind will have notice that, at the end of all years, we will have two Sundayas in a row (three Sundayas if it is a leap year), but I don't think that that would be a major issue, would it?

Example (calendaria for year 15):

Well, in fact, for year 15 and for all years!

Marcha      Aprilia     Maya      Junia
SuMoTu WeThFr Sa SuMoTu WeThFr Sa SuMoTu WeThFr Sa SuMoTu WeThFr Sa
0New Year's Day 123456 0123456 0123456 0123456
78910111213 78910111213 78910Memorial Day 111213 78910111213
14151617181920 14151617181920 14151617181920 14151617181920
21222324252627 21222324252627 21222324252627 21Independence Day observed 22Independence Day 2324252627
Julia      Augusta     Septembra      Octobra
SuMoTu WeThFr Sa SuMoTu WeThFr Sa SuMoTu WeThFr Sa SuMoTu WeThFr Sa
0123456 0123456 0123Labor Day 456 0123456
78910111213 78910111213 78910111213 78910Columbus Day 111213
14151617181920 14151617181920 14151617181920 14151617181920
21222324252627 21222324252627 21222324252627 21222324252627
Novembra      Decembra     Undecembra      Januaria
SuMoTu WeThFr Sa SuMoTu WeThFr Sa SuMoTu WeThFr Sa SuMoTu WeThFr Sa
01Halloween 23456 0123456 0Christmas 123456 0123456
789101112Veterans Day 13 78910111213 78910111213 78910111213
14151617181920 14151617181920 14151617181920 14151617181920
2122232425Thanksgiving Day 2627 21222324252627 2122232425Martin Luther King Day 2627 2122232425Washington's Birthday 2627
SuMoTu WeThFr Sa
29 (*) only if it is a leap year

Some date conversions (US holidays):

January 19 (Martin Luther King Day):

Thursdaya, Undecembra 25.

February 16 (Washington's Birthday):

Thursdaya, Januaria 25.

March 19 (New Year's Eve):

Sundaya, Februaria 28 (or 29, if it is a leap year).

March 20 (New Year's Day):

Sundaya, Marcha 0.

May 25 (Memorial Day):

Wednesdaya, Maya 10.

July 3 (Independence Day observed):

Sundaya, Junia 21.

July 4 (Independence Day):

Mondaya, Junia 22.

September 7 (Labor Day):

Wednesdaya, Septembra 3.

October 12 (Columbus Day):

Wednesdaya, Octobra 10.

October 31 (Halloween):

Mondaya, Novembra 1.

November 11 (Veterans Day):

Fridaya, Novembra 12.

Fourth Thursday of November (Thanksgiving Day):

Thursdaya, Novembra 25 (if we want it on Thursdaya, movable otherwise).

December 25 (Christmas):

Sundaya, Undecembra 0.

Compute your date (1900 onwards):

Enter date (mm/dd/yyyy, for instance: 9/30/2015):


© 2015 Guillermo González Talaván