Calendar Reform Needed?

by Kari Laitinen

Some questions

You have most likely asked questions containing the words 'this year'. Such questions can be like

  • When do the schools start this year?
  • On what day of week is the New Year Day this year?
  • How our wedding day occurs this year?
  • When will we have the annual meeting this year?

If you have been annoyed to find answers to questions like these, this article might be something to read further.

The calendar that we are using makes almonst all people to find answers to questions with 'this year'. If we had a slightly different calendar, most of those questions would be superfluous.

Our current calendar

The western calendar that we are commonly using is officially called Gregorian Calendar as its development was initiated by Pope Gregory XIII. The Gregorian Calendar was taken into use in Roman-Catholic countries in 1582. During the following centuries it was accepted in most countries of the western world.

The Gregorian Calendar is a modification of Julian Calendar which was developed during the days of Julius Caesar, the leader of the Roman Empire.

The following are the essential features of Gregorian Calendar.

  • Time is calculated in years, months, and days. A year corresponds to the time that passes when the Earth circulates the Sun. A day is the time when the Earth rotates once around its own axis. A month resembles the time that the Moon needs to go around the Earth.
  • Every year consists of 12 months that are 28, 29, 30, or 31 days long.
  • Common years have 365 days.
  • Years that are equally divisible by four are leap years which have 366 days. There are some exceptions to this basic rule, but all years divisible by four in the range 2004 ... 2096 are leap years.
  • The extra day that exists in leap years is needed because the circulation time of the Earth around the Sun is not exactly 365 days. The extra day is added to the month February.
  • In addition to years, months, and days, time is measured as weeks in the Gregorian Calendar. A week consists of seven days. Weeks do not relate to any astronomical facts.
  • The beginning of a week is not synchronized with the beginning of a year. For this reason, there are 14 different calendars in the Gregorian system:
    1. Non-Leap Year starting with Monday
    2. Non-Leap Year starting with Tuesday
    3. Non-Leap Year starting with Wednesday
    4. Non-Leap Year starting with Thursday
    5. Non-Leap Year starting with Friday
    6. Non-Leap Year starting with Saturday
    7. Non-Leap Year starting with Sunday
    8. Leap Year starting with Monday
    9. Leap Year starting with Tuesday
    10. Leap Year starting with Wednesday
    11. Leap Year starting with Thursday
    12. Leap Year starting with Friday
    13. Leap Year starting with Saturday
    14. Leap Year starting with Sunday
  • As weeks run independently in relation to years in the Gregorian calendar, the 14 different calendars are taken into use rather randomly. This makes it difficult to plan annual activities with the Gregorian Calendar.
  • There are differences how weeks are displayed in Gregorian Calendars. In the United States it is common to use weeks that start with Sundays. In Europe weeks usually start with Mondays. You can find American-style calendars in figures 1 and 2. Here you can explore more Gregorian Calendars.
Figure 1: Gregorian Calendar for 2025, a non-leap year.

Figure 2: Gregorian Calendar for 2024, a leap year.


The World Calendar

Various proposals have been made to replace the Gregorian Calendar with a modified calendar. Perhaps the most well known of these proposals is the World Calendar, which was developed by Elisabeth Achelis in 1930. She worked hard to make the World Calendar accepted all over the world. Regardless of why the World Calendar was not accepted during the days of Miss Achelis, I think it still is the best proposal to replace the Gregorian Calendar.

The World calendar is very much like the Gregorian Calendar:

  • There are 12 months in both calendars.
  • Leap years are the same and rules related to leap years are the same.
  • Dates in months September, October, November, December, and January are the same in both calendars. In other months there are small differences such as the date April 18 in World Calendar is April 19 in Gregorian Calendar.

The special features of the World Calendar, which make it differ from the Gregorian Calendar, are the following:

  • The World Calendar is a perennial calendar, which means that the same calendar is suitable for all years. To be accurate, there are two versions of the World Calendar: one that is suitable for all non-leap (common) years (see Figure 3) and one that is suitable for all leap years (see Figure 4). Because these calendars differ only so that the leap day is added to the end of June in leap years, we can think that it is a single calendar.
  • There are two days in the World Calendar that do not belong to the usual week system. These are December 31 and June 31. December 31 is called the Worldsday and June 31 is called the Leapyear day. This means that if the World calendar was taken into use, we would have one day every year that would not belong to the usual flow of days of week, and in leap years we would have two such days.
  • With the one or two annual days that are out from the usual flow of days of week the perenniality of the calendar is achieved. These two days could be called days that are no days of week, or they could equally well be called extra Saturdays or extra Sundays during those special weeks.
  • The year is divided into four equal quarters in the World Calendar. Each quarter begins with the same day of week, and has 91 normal days of week.

Small benefits of the World Calendar

The most obvious benefits of a perennial calendar like the World Calendar would be that people would not need to ask questions containing the words 'this year'

  • People would not need to find out when schools begin because they could begin on the same day every year.
  • The New Year Day would always be a Sunday. People would not need to find a calendar to check it.
  • Wedding days could always be celebrated on the same day of week.
  • Annual meetings could always be held on certain dates which would always occur on the same day of week.

Greater benefits of the World Calendar

Many organizations in this world are actually calendar makers. For example, if you Google with the words "school year calendar", you will find out that really many schools publish their calendars and they remake these calendars every year.

With little Googling you can find many kinds of calendars: Government Calendars, Military Pay Calendars, Holiday List Calendars, Sport League Calendars, etc. These calendars are certainly useful, but they would not need to be remade every year if we had a perennial calendar in use.

Using the World Calendar would lessen the need to make and publish annual calendars in various organizations. People could do something more useful than remake internal calendars in organizations

Many activities could be organized in a more rational manner if a perennial calendar was in use. For example, at your car dealer you could have a fixed date reserved for the yearly maintenance of your car, the dates for haircut could always be the same, you could have certain dates to visit your doctor, etc.

Various businesses could arrange special events during the year: restaurants could serve special menus on certain dates, movie theaters could show classic films on certain dates, etc.

The official calendar, like the Gregorian Calendar, is actually a kind of meta-calendar on which organizations base their own calendars. If we had a perennial meta-calendar like the World Calendar, the calendars made in organizations would be perennial as well, and they would not need to be remade every year.

It will not be easy to adopt a new calendar throughout the entire world, but in the long run it would be beneficial for the mankind. A perennial calendar would clarify the concept of a year in our minds, and make it easier to plan and organize the activities we make every year. There would be less complexity and our minds might think something more useful than "on what day of week is that event going to happen this year."

Figure 3: World Calendar for all non-leap years.

Figure 4: World Calendar for all leap years.


Taking the World Calendar in use

Starting to really use the World Calendar would require great agreements between governments and other organizations. I will here discuss some practical matters without any political considerations.

The World Calendar, which starts with a Sunday, could be taken into use in a year that begins with a Sunday in the Gregorian Calendar. Such years are 2034, 2040, and 2045. This way the transition to a new calendar would be rather invisible.

Adopting a new calendar will require modifications in computer systems throughout the entire world. All banks, electricity companies, mobile phones, personal computers, etc. etc. use the present Gregorian Calendar. The software in all these computers should be modified to comply to the new calendar. That would not be easy, but in the long run it would mean a huge business opportunity to all the companies that produce software for computing equipment. The new perennial calendar would simplify computer software in most cases.

It will be necessary that people and companies have something like 5 to 10 years time to prepare for the calendar reform. The governments of different countries, or the United Nations, should make decisions that the new calendar shall be taken into use after 5 years or so. During the transition period software companies should make their software ready for the new calendar.

Some people would have to 'suffer' slightly when the transition to the World Calendar would take place. For example, people who are born on March 31 in the Gregorian Calendar would need to celebrate their birthdays on March 30 or April 1, as date March 31 does not exist in the World Calendar. Other such dates that are missing in the World Calendar are May 31 and August 31.

Generally, dates in months March, April, May, June, July, and August would move 'backwards' with day or two in the transition to the World Calendar. The users of the calendar would not notice these small day movements.

On my World Calendar page you can test how the dates differ between the World Calendar and the Gregorian Calendar. By moving your mouse cursor over a day you should see the differences in the calendars.

How an ordinary person would live the first years with the new calendar?

Let's suppose that the World Calendar is taken into use at the beginning of year 2034. Because the World Calendar starts with a Sunday, and the previous year 2033 ends with Saturday, we could not notice the change of the calendar.

The first time we would notice the new calendar would come after two months since there would be days 29 and 30 at the end of February. Then we would notice the new calendar so that day 31 would be missing from March, April would have day 31, day 31 would be missing from May, and day 31 would be missing from August.

Then, at the end of the year there would be the December 31, 2034, that would be the first Worldsday that is outside the traditional week system. The Wordsday could be considered an extra Saturday or Sunday. Then would follow January 1, 2035, that would be Sunday. Year 2035 would be similar to 2034.

The new calendar would not make the life of an ordinary person difficult. During the last months of year 2034, an ordinary person might see the first benefits of the new calendar.

Let's suppose that an ordinary person works in the offices of some company, and he or she must participate in various meetings. In November 2034, somebody might ask the ordinary person to decide the date of an annual meeting that should be held in February 2035. When the person then takes a look at February 2035 in his/her computer screen, he/she can notice that the calendar application, which is already tailored for the new calendar, suggests that the meeting be held exactly on the same dates as previous year. This makes decision making quite easy.

If the ordinary person is a housewife who is taking care of her children, she might think in December 2034 that what day might the schools start in January 2035. She first plans to call the school, but then she remembers that important dates related to school year are now visible on the main web page of the school, and these dates are even written on a metallic plate that is near the main door of the school.

Let's then suppose that the ordinary person is a university professor who has a habit of organizing an annual scientific seminar which certain people around the world attend. The seminar is always in February and some of the attendees like to come to it because after the seminar they can spend a weekend in a skiing resort that is near the university. Usually the organization of the seminar takes time because the attendees must be informed, hotel rooms must be reserved, etc. So the professor and his secretary start planning the seminar of February 2035 already in October 2034. Then they realize some facts when they read the papers of the previous seminar of February 2034. Because the calendar does not change, they can organize the seminar of February 2035 exactly on the same dates as it was organized in February 2034. They can reserve hotel rooms for the same dates as previous year. Even the attendees can use the same flights when coming to the seminar. After discovering this, the professor decides that the seminar will always be on the same dates in February. The fixed seminar dates help also the attendees. Some of them can now make permanent reservations for a certain February weekend in the hotel in the nearby skiing resort.

Calendars and the conception of time

I am afraid that presently there is no clear conception of time in our minds because on the one hand we are measuring time in years and months, and on the other hand we are measuring time in 7-day weeks, and these two scales for time measurement are not synchronized. That confuses our minds and prevents us from making a clear conception of time.

There are 14 different kinds of years in the Gregorian Calendar and these possible years follow each other in a somewhat random order. If there were a single calendar for every year, our minds would not need to work so much.

Presently we do have a clear conception of a week. To make a perennial calendar, we should slightly modify the concept of a week. This modification would certainly cause some confusion but by making this sacrifice we would get a chrystal-clear conception of a year. It is better if we can plan the future in years than just in 7-day periods.

A perennial calendar whose years are always the same might also modify our conception of time so that we could trust more on the years that are ahead of us. The future is always not known and insecure. If there were a calendar that would be the same in all the coming years, there would be one thing less insecure in the future. This could increase optimism in people's minds, and make this world a little bit better.

The 7-day week system has been used maybe more than 4000 years. According to Elisabeth Achelis, who divoted her life to the promotion of the World Calendar, the 7-day week system was introduced to Palestine by the Assyrians. Weeks were not used in the original Julian Calendar that was thus perennial. The 7-day week was introduced to the Julian Calendar by Emperor Constantine, and that made the calendar to loose its perenniality. It is important to note that the Roman Empire experienced its most heroic times during those centuries when a perennial calendar was in use. The Ancient Egyptians were also using a perennial calendar, and their culture is quite remarkable as well.

About some other calendar proposals

The World Calendar is not the only one that has been suggested as a replacement for the Gregorian Calendar. If you visit the calendar pages of Rick McCarty you will find out information about many calendar proposals.

One famous proposal to replace the Gregorian Calendar is a 13-month calendar. I am afraid, however, that this calendar would not be accepted because it differs so remarkably from the existing calendar.

The number 12 that is the number of months in both the World Calendar and the Gregorian Calendar is actually quite a beautiful number. Being equally divisible by 2, 3, 4, and 6, the number 12 suits well to calculations related to the time.

There has already been one failed attempt to change our present calendar system. After the French revolution, in 1793, the French revolutionaries started to use a new calendar which was quite different from our present Gregorian Calendar. The French Revolutionary Calendar has 10-day weeks, 3 weeks in each of its 12 months, and the year end is filled with public holidays. The French Revolutionary calendar was used about 12 years but Emperor Napoleon decided to re-establish the Gregorian Calendar. I think the main reason that the French Revolutionary Calendar was abandoned, is that the new calendar was too much different from the old one.

Because the World Calendar is very much similar to our present Gregorian Calendar, it is easy to start using it. In addition, when the World Calendar is in use, it is easy to read documents that were written during the time when the old Gregorian Calendar was still in use. Also after a calendar reform it must be possible to read texts that contain dates according to the old calendar. Because the dates in the World Calendar and the Gregorian Calendar differ only slightly, interpreting old dates will not be problematic.

Why did I write this?

Throughout my entire life, I have been interested in calendars. I do not know why. I still remember how exciting it was that, as a child, I could every year fetch a new free calendar from a local hardware store. I have often bought a different kind of calendar for every year, and I have collected calendars printed in different countries.

I became truly interested in calendars in 1997, when I wrote a computer program which can be used to generate calendars according to our present calendar system. Then I could also find information about proposals for a perennial calendar. I immediately understood the deficiencies of the Gregorian Calendar, and I became a supporter of the reformation of our calendar system. It is unfair that people have to do unnecessary activities because of a calendar that changes every year.

I have devoted quite much time to writing the text of this page. Every now and then I have wondered if this makes sense. Then I have realized that, after all, it is quite remarkable to continue the work that has previously been carried out by a person like Julius Ceasar.

Currently I do not have time and energy to arrange a calendar reformation or revolution, but I can be supportive if a new Julius Caesar or Elisabeth Achelis emerges.


Dr. Carmen Martínez Carrillo has given clever comments to an earlier version of this page.

Mikko Laurila has pointed out that there are actually 15 different calendars in our present calendar system if we take into account the week numbers that are in use in many countries. The first days of common years that start with a Saturday can belong either to week 52 or 53, which makes one more possible calendar in addition to the 14 different Gregorian calendars.

I would like to emphasize that the World Calendar of which this page mostly tells is not invented by me. It was invented by Elisabeth Achelis.


Calendar pages of Rick McCarty.

Calendar Page of George Boeree, and check also his other pages.

My page which shows the WorldCalendar

My page which shows the Gregorian Calendar for many years.

Calendars are used to time the life of humans in years, months, and days. In many human activities we need to measure time in shorter units. For example, in the field of music, people time music by using units such as 'measures', 'bars', or 'beats', and they use tools like metronomes to help in timing.

If you happen to be a musician, this metronome called BARBARA might be of interest to you as it measures music in bars rather than in beats.