Basic Information Edit

The Common Calendar uses the same twelve months of the year as we do now, but with different lengths. Every year will start on Sunday 1 January, and every quarter year (not just year, but... QUARTER YEAR) will be identical. The first month of each quarter year (January, April, July and October) will start on a Sunday and have 31 days, finishing on a Tuesday. The second month (February, May, August and November) will start and end on a Wednesday and will each have 29 days. The final month (March, June, September and December) will start on a Thursday and have 31 days, ending on a Saturday and thus allowing the following quarter year to begin on the Sunday previously mentioned. As a result, Christmas Day (25 December) and New Year's Day (1 January) will always, without exception, fall on Sundays.

With this maths, we see that the year contains only 364 days each year. So, how do we account for the fact that the solar year (the determinant of the seasons) lasts 365.242199 days? Simple. We insert an extra week in certain years, rather than an extra day. To determine which years have this extra day, we use the Base System. Due to the pattern of the solar year I have given the base number of -3 to the year 2009. So then which number goes to 2010? Under the Common Calendar, 2009 would have had 364 days, which is 1.242199 days less than the solar year. So we add 1.242199 to -3 to get the base number of -1.757801 in 2010. We continue to add this number to the year - but the number must ALWAYS be between -3.5 (inclusive) and +3.5 (exclusive). So, by the time we get to 2013, the base number is +3.210995. What happens in 2014, when the base number would be +4.453194? We must subtract seven to give 2014 a base number of -2.546806.

BUT, to be able to legitimately do that, we must insert an extra seven days in the year 2013. This is done through a week called INTERCALARIS, which is inserted between Saturday 31 June and Sunday 1 July, 2013. The days of the week are simply "Sunday of Intercalaris," "Monday of Intercalaris" etc. and are not numbered in the same way that the months have their days numbered. Intercalaris is not a month; it is an "intercalary week." These years are also no longer known as leap years but as "intercalary years." The name leap year probably originates from the fact that the calendar "leaps" over one day of the week (i.e. Christmas day was a Saturday in 2010 and a Sunday in 2011, but in leap year 2012 will not be Monday but Tuesday). Of course, this does not happen in the Common Calendar. To keep from mucking up business quarters and the like, Intercalaris will be a worldwide holiday. The seven day week will be preserved and the days will be named as they usually are in the week, but every day will be treated as though it were a Sunday. Basically all this means is that if your business closes on a Sunday normally under the current system, it will close during Intercalaris.

On the other hand, with Christmas and New Year fixed on Sundays, there will be no regular closing of businesses between Christmas and New Year as often exists in today’s society. It seems fair, though, that at Christmas and Easter, to aid family time and other similar things, that people be given a brief, standard recess of Friday to Monday (23-26 Dec / 6-9 Apr) over these times. Ideally, these dates could be legal holidays in all observing countries, but if not then I would propose that these recesses be given to standard workers in a similar way as the Christmas-New Year break is now.

Some people have proposed a system whereby the year is kept with the same number of days as our current, Gregorian calendar, with the 365th and 366th days of the year being proposed as "blank days" not belonging to any week, to keep the calendar the same from year to year. Religious leaders in the Abrahamic Religions, accounting the majority of the world's population (Christianity occupying 33% and Islam a further 20%, with Judaism being smaller) have formally rejected this on the grounds that it violates the structure of the Sabbath as God intended. Such a calendar will never be used formally - the opposition has always been, and will always be, too strong. One may say that this system of adding these numbers to a base year is much too complicated - but only if you have to do it! And you won't!! All you need to remember is that intercalary years take place every five to six years and keep an eye out for the calendar!! Let your servants in publishing take care of that for you while you relax!!!

One last thing will be tidied up - the "moon-wandering" Easter Sunday to different dates in the months of March and April. How annoying is that - never knowing when Easter is going to be from one year to the next. How badly did it throw you off in 2011 when Easter was the latest it had been in 68 years? Or back in 2008, when it was the earliest in 95 years? Under the Common Calendar, the date of Easter Sunday will always, without fail, be Sunday 8 April. While there are many difficulties dating the crucifixion of Jesus, most scholars will assert it was either on Friday 7 April, AD 30 or Friday 3 April, AD 33, making the Resurrection Day 9 April or 5 April. Neither of these dates are Sundays in the Common Calendar, and most Christians unanimously agree that this celebration needs to take place on a Sunday. Thus, I have chosen Sunday 8 April, which falls between the two dates. If your birthday is 6 April you will be upset as your birthday will always be Good Friday - but nothing can be perfect for everyone!!

Layout Edit

As we can see - we are left with a calendar which is MUCH SIMPLER than the one we are left with now. Please support a conversion to this on 1 JANUARY 2023!

January, April, July, October
Week 1 2 3 4 5 6 7
Sun Mon Tue Wed Thu Fri Sat
01/14/27/40 01 02 03 04 05 06 07
02/15/28/41 08 09 10 11 12 13 14
03/16/29/42 15 16 17 18 19 20 21
04/17/30/43 22 23 24 25 26 27 28
05/18/31/44 29 30 31
February, May, August, November
Week 1 2 3 4 5 6 7
Sun Mon Tue Wed Thu Fri Sat
05/18/31/44 01 02 03 04
06/19/32/45 05 06 07 08 09 10 11
07/20/33/46 12 13 14 15 16 17 18
08/21/34/47 19 20 21 22 23 24 25
09/22/35/48 26 27 28 29
March, June, September, December
Week 1 2 3 4 5 6 7
Sun Mon Tue Wed Thu Fri Sat
09/22/35/48 01 02 03
10/23/36/49 04 05 06 07 08 09 10
11/24/37/50 11 12 13 14 15 16 17
12/25/38/51 18 19 20 21 22 23 24
13/26/39/52 25 26 27 28 29 30 31
Intercalaris 01 02 03 04 05 06 07

FAQ Edit

  1. Would it not be a whole lot easier just to leave things the way they are?
    Answer: It depends on how you look at it. In the one sense, yes, because you wouldn’t have to have the initial upheaval in the first year or so whereby the calendar changes quite a bit from the way you know it. But in almost all aspects, absolutely not. Once this calendar ...takes off, you will never need to worry about making annual schedules every year. Those things you do every year, you can schedule on a particular date in 2023 when this calendar comes into effect, and there is no reason it can’t stay on the same date every year.
  2. Why 2023?
    Answer: Easy. As described, each year begins on Sunday 1 January and ends on Saturday 31 December. I have chosen this point as the transition because, under our current Gregorian Calendar, the year 2022 ends on Saturday 31 December, so a transition to Sunday 1 January 2023 under the Common Calendar is extremely smooth.
  3. Why call it the Common Calendar?
    Answer: For simplicity. The intention is that after 2023, it will be in common use throughout the world. The Common Calendar provides a quick and easy name, and most people would think of the “common calendar” as opposed to calendars they may use for business, academic, sacred or other purposes anyway.
  4. Why have the two 31-day months with the 29-day month in the middle?
    Answer: For symmetry. I mentioned that I had organised for Christmas and New Year to both be Sundays. This would require the month of December (and also the last month of every quarter to not wreck the equal quarters) to have 31 days (unless they had 30 days and one defined Christmas Day as Sunday 24 December and Saturday 23rd as Christmas Eve – but that wouldn’t take off, it’s too radical a change). We could have the two 30-day months and the last month of each quarter would have 31, but that would be less symmetrical. This way, the months look the same from back-to-front as from front-to-back. This would aid businesspeople and statisticians to do their work.
  5. But why can’t you fix Christmas on a Monday and New Year’s Day on a Sunday?
    Answer: Do you really want Christmas Day to be always on a Monday? As it stands now, Sunday (although to a lesser extent than 100 years ago) is the least active day of the week for workers, and Christmas Day is the least active day of the year for workers. So to have Christmas Day coincide with Sunday makes it all fall neatly into place. On the other hand, Christmas Eve is generally a very busy day of the year for a lot of workers, including those who don’t usually have to work Sundays. How many workers are forced to open up on a Sunday 24 December to get their business done before Christmas? Too many. You’ll be too widely-hated if you allow Christmas Eve to be forced onto a Sunday every year. Besides, people are used to New Year’s Eve being the 31st anyway. For it to be suddenly the 30th would confuse in a way that few other holidays would change to be confused by changes to month lengths.
  6. It’s not fair! My birthday will always be on a Wednesday whereas my wife always gets hers on a Saturday. How does that work out?
    Answer: Can everything work out exactly the same for everyone in life? In any event, this calendar does allow for everyone to celebrate their birthday on any nearby weekend date they choose if they need a day to celebrate.
  7. Help! I’m going into labour and it’s Intercalaris. My baby will only have a birthday every five or six years!
    Answer: Easy enough! The child is being born on a day in that week which ends the second quarter year. So the child’s birthday takes place in the last week of the second quarter year. Suppose the child is born on the Tuesday. So celebrate the child’s birthday on the Tuesday at the end of the second quarter year – usually 27 June.
  8. But what if your birthday is removed at the end of the month?
    Answer: Easy. The last day of certain months has been removed. Say your birthday was on 30 November. You have two very clear options, and you can officiate either. Since you were born on the last day of November – celebrate your birthday on the last day of November, the 29th. Or, since you were born 30 days from the first of the month, celebrate your birthday 30 days from the first of the month, on 1 December after the 29-day month.
  9. But what about May and August? They lose TWO days at the end of the month!
    Answer: I do actually realise that – it’s my calendar after all! A little bit more tricky but can still be dealt with. If the penultimate and last days of the month (30 and 31 May/August) are the days you were born, one can celebrate one’s birthday on the penultimate and last days of the month (28 and 29 May/August). Or, if you were born on the 30th and 31st days from the first of the month (30 and 31 May/August), you can celebrate your birthdays on the 30th and 31st days from the first of the month (1 and 2 June/September). There is a third option here as well – under our calendar, the closest date to 30 May/August which will not be removed is 29 May/August, and the closest to 31 May/August which will not be removed is 1 June/September, so birthdays can be transferred in this way. I really don’t mind – it’s up to you!
  10. I’m worst off – my birthday is 6 April. Good Friday every year!!
    Answer: I’m sorry to have done this to you, but if Easter is to be fixed it has to happen to someone. I have to be objective and 6 April is, from a historical perspective, most appropriate for the reasons I have discussed. But like anyone, why not celebrate your birthday on a better day – celebrate it on Easter Monday once a lot of festivities have died down. It’s only three days difference and you get a much happier birthday.
  11. I work the land. I’m used to planting on 21 March, but since 21 March moves around in the solar year so much it will go wrong.
    Answer: Use the base number. Round it to the nearest whole number and add that number from the date. If the base number is near 2, for example, plant on 21+2=23 March. If it’s near -2, then, plant on 21-2=19 March.
  12. Stuff all!
    Answer: Then you will have to deal with ongoing calendar changes for the rest of your life. It’s quite different, but it will save you a lot of stress after the first year or so.

Concessions Edit

Possible Edit

  1. The lengths of the months. I will concede to having the first two months of each quarter with 30 days, and the final month having 31. The final month must have 31 days, thus allowing 25 December and 1 January to always be Sundays.
  2. The leap year rule. I will concede, rather than my Base System, to use the rule proposed by Dr. Irv Bromberg in his Symmetry454 and Symmetry 010 Calendars. “It is a leap year only if the remainder of (52 × Year + 146 ) / 293 is less than 52.” I give reference to these pages for this rule - I DO NOT OWN THEM:
  3. The name Intercalaris. The word intercalary is a common adjective meaning to do with being inserted into certain years (like our current 29 February), and the old Roman calendar, of which ours is an off-shoot, had a 22 or 23-day period in certain years sometimes called Intercalaris (although it was in February). So I have used that name for historical reasons. But I really don't care what you call it. It could be anything. (Like Mercedonius - another name the Romans used for their Intercalaris.) It could even be between September and October if you'd rather. But not between March and April, as that would muck around Easter dates for religious people; or between December and January, as that would do the same to Christmas. I just thought June and July was easier than September and October because it's mid-year rather than three-quarters. But it's not the be all and end all of my calendar.

Impossible Edit

  1. The occurrence of 1 January and 25 December always on Sundays.
  2. Every quarter year being equal
  3. A constantly uninterrupted seven-day week - MOST IMPORTANTLY!!

Popular Observances Edit

  • Sunday 1 January – New Year’s Day
  • Saturday 17 March – St Patrick’s Day
  • Sunday 1 April – April Fool’s Day
  • Sunday 12 May – Mother’s Day – The celebration of Mother’s Day, while fairly universal, has not been set to a standardised date, so the Common Calendar standardises it on this Sunday, the traditional date in both the Commonwealth of Australia and the United States of America.
  • Sunday 18 June – Father’s Day – The celebration of Father’s Day, while fairly universal, has not been set to a standardised date, so the Common Calendar standardises it on this Sunday, the traditional date in both the United Kingdom and the United States of America.
  • Sunday 8 July – Summerfest (Winterfest) Day – A tradition I started in 2007, it allows for the cultural aspects of Christmas relating to summer (for the Southern Hemisphere [mainly Australian and New Zealand customs]) / winter (for the Northern Hemisphere) to be celebrated in each other’s hemispheres.
  • Sunday 4 September – Grandparents’ Day – While the celebration of Mother’s Day and Father’s Day are fairly universal, Grandparents’ Day is only widely observed in the United States. The Common Calendar spreads it to the rest of the world, although brings it forward one week to avoid a clash with World Peace Day.
  • Sunday 11 September – World Peace Day – Observed on the anniversary of the attack on the Twin Towers in New York City, USA in 2001, this day invites people around the world to remember the reality of uncertainty and conflict in our world and to renew their efforts and desires for world peace.
  • Wednesday 1 November – All Saints’ Day – The notion of Halloween re-christened, the idea of scary blood and gore costumes is out. Instead, under the Common Calendar, children of Christian faith will attend church with their families (the 1st November church service or Mass) in the early evening of Tuesay 31 October (typically 5 pm), and then will go collecting candy and exchanging scripture verses, dressed as their favourite saint. All schools (for students of all ages, not only young children) will dismiss children on Tuesday 31 October at whatever is the usual time for the start of the lunch break, to allow for the celebration. Total closure of schools on Wednesday 1 November is optional and to be left to the discretion of the school itself or of the relevant school authority.

School Calendars By Country Or Region Edit


The school calendar observed in Australia under the Common Calendar is more symmetrical, provides a sufficient number of teaching and training days, and is more consistent between states and territories and between public, religious and independent schools:

ALL schools in Australia observe the following calendar each year (whether they are public, religious or independent):

  • Wed 25 Jan to Thu 05 Apr (51 days)
  • Mon 30 Apr to Fri 30 Jun (44 days)
  • Thu 12 July to Fri 23 Sept (51 days)
  • Mon 09 Oct to Tue 13 Dec* (47 days)
  • Total: 193 days
  • Mon 30 Jan to Thu 05 Apr (49 days)
  • Mon 30 Apr to Fri 30 Jun (44 days)
  • Mon 16 July to Fri 23 Sept (49 days)
  • Mon 09 Oct to Fri 09 Dec* (45 days)
  • Total: 187 days

Dates marked with * indicate that independent schools can use a different (although nearby) date (earlier or later) to attain an exact number of schooldays which they seek, as long as there are two training days after the last teaching day.

I have decided to move the three-week break to which most independent schools ae accustomed, to the Easter holidays rather than in the middle of the year. This both avoids having ANZAC Day in the middle of the first week of Term 2, as well as providing more ability for school holiday travel for people intending to travel where spring and autumn are the best time (which is the case for many travel destinations).


The school calendar observed in Great Britain and Irenald under the Common Calendar uses a four-term year to provide more consistency with business quarters as well as alignig with the season, and is more consistent between states and territories and between public, religious and independent schools:

ALL schools in Great Britain and Ireland observe the following calendar each year (whether they are public, religious or independent):

  • Wed 08 Aug to Fri 13 Oct
  • Mon 23 Oct to Thu 22 Dec
  • Thu 12 Jan to Fri 30 Mar
  • Mon 23 Apr to Tue 27 Jun*
  • Mon 13 Aug to Fri 13 Oct
  • Mon 23 Oct to Thu 22 Dec
  • Mon 16 Jan to Fri 30 Mar
  • Mon 23 Apr to Fri 23 Jun*

Dates marked with * indicate that independent schools can use a different (although nearby) date (earlier or later) to attain an exact number of schooldays which they seek, as long as there are two training days after the last teaching day.

Public Holidays By Country Or Region Edit

For the most part, local holidays will remain on the same date. There will, however, be minor changes. The celebration of the Queen's Birthday observance in Australia and New Zealand, scattered to different dates throughout the area, will be standardised as a public holiday on Monday 5 June. The intention of fixing the date rather than having it change with the monarch was to keep it close to 3 June, the birthday of King George V. Easily the nearest Monday to this is 5 June, hence this is the date on which the holiday will be fixed throughout Australia and New Zealand. There will no longer be a Foundation Day holiday in Western Australia. In addition, Australia will observe two new holidays: one on Saturday 3 June itself, called Mabo Day (to celebrate the Mabo decision pertaining to Aboriginal Australians in the High Court in 1992 and a celebration of the nation's Aboriginal heritage in general); and on Wednesday 8 August, called Saint Mary MacKillop's Day (the death of celebrated Australian saint and cultural icon Mary MacKillop). Furthermore, all holidays specific to an Australian state or territory will be removed; a Labour Day holiday will be observed nationwide throughout Australia on Monday 2 October (the most common date in the country).

The bank holiday traditionally on the last Monday in May in the United Kingdom, and on the first Monday in June in the Republic of Ireland, will be moved to the last Monday in May (27 May) in both, as historically it was the day after Pentecost Sunday, having been changed in recent decades to prevent another floating holiday. Now that Pentecost Sunday is fixed on 26 May, it seems more logical to fix this bank holiday on 27 May in both.

I would personally prefer, now that holidays are fixed on their dates, that United States federal holidays be returned to their traditional dates (although a weekday can still be used if the date in question is a Saturday or Sunday). This would leave the following:

  • New Year's Day: Sunday 1 January
  • MLK Junior Day: Monday 16 January
  • Washington's Birthday: Wednesday 22 February
  • Memorial Day: TBA (use the same procedure I previously described for 30 May birthdays)
  • Independence Day: Wednesday 4 July
  • Labor Day: Monday 5 September
  • Columbus Day: Thursday 12 October
  • Veteran's Day: Friday 10 November
  • Thanksgiving Day: Thursday 23 November
  • In addition, I would prefer that the United States observe the Friday-to-Monday recesses over Christmas and Easter.

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