# Does the date of Easter favor some dates over others? **URL:** \ **Category:** Factual Questions\ **Created:** [April 18, 2025, 3:48pm UTC](https://boards.straightdope.com/t/does-the-date-of-easter-favor-some-dates-over-others/1017173 "2025-04-18T15:48:29Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![HeyHomie](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/heyhomie/32/207_2.png) [@HeyHomie](https://boards.straightdope.com/u/HeyHomie)\ **Post date:** [April 18, 2025, 3:48pm UTC](https://boards.straightdope.com/t/does-the-date-of-easter-favor-some-dates-over-others/1017173/1 "2025-04-18T15:48:29Z")
I know that there are 35 possible days which can be Easter Sunday, but over the millennia, has the distribution been consistent across all 35 dates? Is there a one in 35 chance that any Easter will be on 4/20? Or does the dance of the earth and the moon mean some dates are more likely than others? ---
**Author:** ![kenobi\_65](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/kenobi_65/32/13178_2.png) [@kenobi\_65](https://boards.straightdope.com/u/kenobi_65)\ **Post date:** [April 18, 2025, 4:01pm UTC](https://boards.straightdope.com/t/does-the-date-of-easter-favor-some-dates-over-others/1017173/2 "2025-04-18T16:01:33Z")
> [@HeyHomie](#): > > but over the millennia, has the distribution been consistent across all 35 dates? I’m not sure about _millennia_, but this page shows the distribution from 1600 to 2099 (i.e., a sample size of 500 years), and no, it’s not been/will be evenly distributed. Occurrence on the earliest possible dates (March 22-25) and latest possible dates (April 23-25) are much lower. Even among the other dates, there are a few (March 31, April 5, April 11, April 16), which have happened a bit more often. Technically, my birthday (March 24) _can_ be Easter, but as a kid, I was saddened to learn that the last time it happened was 1940, and would not happen again until 2391. > **[Frequency of the Date of Easter 1600 to 2099](https://www.census.gov/data/software/x13as/genhol/easter-dates-frequency.html)** > > This page contains the frequency of occurrence of the date of Easter for a 500 year period taken from a public listing of Easter dates published by M. Bednarek. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [April 18, 2025, 4:16pm UTC](https://boards.straightdope.com/t/does-the-date-of-easter-favor-some-dates-over-others/1017173/3 "2025-04-18T16:16:24Z")
The date of Easter is set as “The first Sunday after the first full moon after March 21”. So you’ve got three different cycles (the yearly cycle, the lunar cycle, and the weekly cycle). These three cycles are unrelated to each other, with the ratio of any two of the periods being presumably irrational, so averaged over all of time, where you are in each cycle is essentially random with respect to each other. So basically, every year has a March 21. Then, roll (approximately) 1d28 to determine where you are in the lunar cycle, and then roll 1d7 to determine where you are in the weekly cycle. ---
**Author:** ![Jas09](https://avatars.discourse-cdn.com/v4/letter/j/d07c76/32.png) [@Jas09](https://boards.straightdope.com/u/Jas09)\ **Post date:** [April 18, 2025, 4:32pm UTC](https://boards.straightdope.com/t/does-the-date-of-easter-favor-some-dates-over-others/1017173/4 "2025-04-18T16:32:09Z")
Wikipedia has some nice charts, in addition to what @kenobi_65 posted. Here is one for the entire 5.7million year cycle: [Date of Easter - Wikipedia](https://en.wikipedia.org/wiki/Date_of_Easter#/media/File:Easter_dates,_full_cycle.svg) It is exceedingly complicated. ---
**Author:** ![bob\_2](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bob_2/32/3341_2.png) [@bob\_2](https://boards.straightdope.com/u/bob_2)\ **Post date:** [April 18, 2025, 4:35pm UTC](https://boards.straightdope.com/t/does-the-date-of-easter-favor-some-dates-over-others/1017173/5 "2025-04-18T16:35:33Z")
> [@HeyHomie](#): > > 35 possible days which can be Easter Sunday Surely, there are only four possible Sundays - or is it five? ---
**Author:** ![HeyHomie](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/heyhomie/32/207_2.png) [@HeyHomie](https://boards.straightdope.com/u/HeyHomie)\ **Post date:** [April 18, 2025, 4:39pm UTC](https://boards.straightdope.com/t/does-the-date-of-easter-favor-some-dates-over-others/1017173/6 "2025-04-18T16:39:21Z")
Yes, but any of those sundays could be any date between March 21 and April Whatever. ---
**Author:** ![jnglmassiv](https://avatars.discourse-cdn.com/v4/letter/j/f07891/32.png) [@jnglmassiv](https://boards.straightdope.com/u/jnglmassiv)\ **Post date:** [April 18, 2025, 4:42pm UTC](https://boards.straightdope.com/t/does-the-date-of-easter-favor-some-dates-over-others/1017173/7 "2025-04-18T16:42:03Z")
> [@Jas09](#): > > Here is one for the entire 5.7million year cycle: [Date of Easter - Wikipedia](https://en.wikipedia.org/wiki/Date_of_Easter#/media/File:Easter_dates,_full_cycle.svg) That’s a great visual. ---
**Author:** ![kenobi\_65](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/kenobi_65/32/13178_2.png) [@kenobi\_65](https://boards.straightdope.com/u/kenobi_65)\ **Post date:** [April 18, 2025, 4:44pm UTC](https://boards.straightdope.com/t/does-the-date-of-easter-favor-some-dates-over-others/1017173/8 "2025-04-18T16:44:19Z")
> [@Jas09](#): > > Here is one for the entire 5.7million year cycle: [Date of Easter - Wikipedia](https://en.wikipedia.org/wiki/Date_of_Easter#/media/File:Easter_dates,_full_cycle.svg) One of the fascinating things about that chart is that distribution of the occurrences from March 28th through April 20th is pretty consistent, at about 3.4%…except for April 19th, which is nearly 4%. ---
**Author:** ![burpo\_the\_wonder\_mutt](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/burpo_the_wonder_mutt/32/365_2.png) [@burpo\_the\_wonder\_mutt](https://boards.straightdope.com/u/burpo_the_wonder_mutt)\ **Post date:** [April 18, 2025, 4:45pm UTC](https://boards.straightdope.com/t/does-the-date-of-easter-favor-some-dates-over-others/1017173/9 "2025-04-18T16:45:25Z")
I was always told Easter was the first Sunday after the first full moon after the _Vernal equinox_ which is not always on March 21. My birthday is April 11 and Easter was on my birthday in 1971, 1982, 1993 and 2004. Then when I’m getting in the groove, it jumps to 2060 which is the 100th anniversary of my birth. I expect many presents and Peeps. ---
**Author:** ![Pleonast](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/pleonast/32/1183_2.png) [@Pleonast](https://boards.straightdope.com/u/Pleonast)\ **Post date:** [April 18, 2025, 4:49pm UTC](https://boards.straightdope.com/t/does-the-date-of-easter-favor-some-dates-over-others/1017173/10 "2025-04-18T16:49:22Z")
> [@burpo\_the\_wonder\_mutt](#): > > I was always told Easter was the first Sunday after the first full moon after the _Vernal equinox_ which is not always on March 21. That was mine understanding as well. The date of the vernal equinox is kept approximately, but noncontinuously, constant with leap days. So that puts in another 400-year cycle. ---
**Author:** ![burpo\_the\_wonder\_mutt](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/burpo_the_wonder_mutt/32/365_2.png) [@burpo\_the\_wonder\_mutt](https://boards.straightdope.com/u/burpo_the_wonder_mutt)\ **Post date:** [April 18, 2025, 4:53pm UTC](https://boards.straightdope.com/t/does-the-date-of-easter-favor-some-dates-over-others/1017173/11 "2025-04-18T16:53:06Z")
That Dionysius Exiguus was a real card, wasn’t he? 🤪 ---
**Author:** ![Pleonast](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/pleonast/32/1183_2.png) [@Pleonast](https://boards.straightdope.com/u/Pleonast)\ **Post date:** [April 18, 2025, 4:54pm UTC](https://boards.straightdope.com/t/does-the-date-of-easter-favor-some-dates-over-others/1017173/12 "2025-04-18T16:54:53Z")
> [@Pleonast](#): > > > [@burpo\_the\_wonder\_mutt](#): > > > > I was always told Easter was the first Sunday after the first full moon after the _Vernal equinox_ which is not always on March 21. > > That was mine understanding as well. But it appears the actual computation uses a simplified lunar cycle and a simplified equinox rather than the actual astronomical phenomena. Cheaters! 😉 ---
**Author:** ![burpo\_the\_wonder\_mutt](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/burpo_the_wonder_mutt/32/365_2.png) [@burpo\_the\_wonder\_mutt](https://boards.straightdope.com/u/burpo_the_wonder_mutt)\ **Post date:** [April 18, 2025, 4:57pm UTC](https://boards.straightdope.com/t/does-the-date-of-easter-favor-some-dates-over-others/1017173/13 "2025-04-18T16:57:11Z")
Oh, I had a nasty case of simplified equinox about 3AM this morning. I blame week old spaghetti for dinner. 😄 ---
**Author:** ![Northern\_Piper](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/northern_piper/32/5304_2.png) [@Northern\_Piper](https://boards.straightdope.com/u/Northern_Piper)\ **Post date:** [April 18, 2025, 5:03pm UTC](https://boards.straightdope.com/t/does-the-date-of-easter-favor-some-dates-over-others/1017173/14 "2025-04-18T17:03:55Z")
> [@Pleonast](#): > > That was mine understanding as well. The date of the vernal equinox is kept approximately, but noncontinuously, constant with leap days. So that puts in another 400-year cycle. That was the reason for the Gregorian reform: the vernal equinox and the calendar days were getting out of synch over the centuries. ---
**Author:** ![gnoitall](https://avatars.discourse-cdn.com/v4/letter/g/bb73d2/32.png) [@gnoitall](https://boards.straightdope.com/u/gnoitall)\ **Post date:** [April 18, 2025, 5:08pm UTC](https://boards.straightdope.com/t/does-the-date-of-easter-favor-some-dates-over-others/1017173/15 "2025-04-18T17:08:36Z")
> [@burpo\_the\_wonder\_mutt](#): > > Dionysius Exiguus When everyone calls you Short Dennis to your face, you develop either a sense of humor or a scarcely-suppressed murderous rage. Or both. ---
**Author:** ![Jas09](https://avatars.discourse-cdn.com/v4/letter/j/d07c76/32.png) [@Jas09](https://boards.straightdope.com/u/Jas09)\ **Post date:** [April 18, 2025, 5:11pm UTC](https://boards.straightdope.com/t/does-the-date-of-easter-favor-some-dates-over-others/1017173/16 "2025-04-18T17:11:27Z")
Yes… like I said it’s extremely complicated because the math is based on historical comprises, changes in the calendar (Gregorian v. Julian) and various “cheats”. Gauss had an interesting algorithm you can read about here: [Date of Easter - Wikipedia](https://en.wikipedia.org/wiki/Date_of_Easter#Gauss's_Easter_algorithm) The key point there is the special cases at the bottom: > [@](#): > > if _d_ = 28, _e_ = 6, and (11_M_ + 11) mod 30 \< 19, replace 25 April with 18 April > if _d_ = 29 and _e_ = 6, replace 26 April with 19 April That second one is what makes April 19th overrepresented, and April 26 not appear at all. I can’t actually follow most of it, but the key seems to be some agreement made a long time ago: > [@](#): > > For reasons of historical compatibility, all offsets of 35 and some of 34 are subtracted by 7, jumping one Sunday back to the day of the full moon (in effect using a negative _e_ of −1). This means that 26 April is never Easter Sunday and that 19 April is overrepresented. These latter corrections are for historical reasons only and have nothing to do with the mathematical algorithm. The offset of 34 is adjusted if (and only if) _d_ = 28 and _d_ = 29 elsewhere in the 19-year cycle. ---
**Author:** ![Jas09](https://avatars.discourse-cdn.com/v4/letter/j/d07c76/32.png) [@Jas09](https://boards.straightdope.com/u/Jas09)\ **Post date:** [April 18, 2025, 5:15pm UTC](https://boards.straightdope.com/t/does-the-date-of-easter-favor-some-dates-over-others/1017173/17 "2025-04-18T17:15:04Z")
> [@burpo\_the\_wonder\_mutt](#): > > I was always told Easter was the first Sunday after the first full moon after the _Vernal equinox_ which is not always on March 21. No, I don’t think that’s right. It is defined based on the “paschal full moon”, which is based on the “ecclesiastical equinox” which is fixed at March 21. And this “paschal full moon” doesn’t have to actually be a full moon - it’s just a computation. ---
**Author:** ![DPRK](https://avatars.discourse-cdn.com/v4/letter/d/4491bb/32.png) [@DPRK](https://boards.straightdope.com/u/DPRK)\ **Post date:** [April 18, 2025, 5:32pm UTC](https://boards.straightdope.com/t/does-the-date-of-easter-favor-some-dates-over-others/1017173/18 "2025-04-18T17:32:33Z")
It is always going to be a simplified computation unless the church decides its calendar is going to be fixed to the actual astronomical phases of the moon and Earth’s orbit. The same may be said for the Jewish computus. ---
**Author:** ![FinsToTheLeft](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/finstotheleft/32/2930_2.png) [@FinsToTheLeft](https://boards.straightdope.com/u/FinsToTheLeft)\ **Post date:** [April 18, 2025, 5:34pm UTC](https://boards.straightdope.com/t/does-the-date-of-easter-favor-some-dates-over-others/1017173/19 "2025-04-18T17:34:15Z")
> [@DPRK](#): > > The same may be said for the Jewish computus. My birthday ends up during Passover every few years. Flourless birthday cake is disappointing. ---
**Author:** ![BigT](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bigt/32/12044_2.png) [@BigT](https://boards.straightdope.com/u/BigT)\ **Post date:** [April 18, 2025, 5:57pm UTC](https://boards.straightdope.com/t/does-the-date-of-easter-favor-some-dates-over-others/1017173/20 "2025-04-18T17:57:38Z")
> [@FinsToTheLeft](#): > > > [@DPRK](#): > > > > The same may be said for the Jewish computus. ⁢ > > My birthday ends up during Passover every few years. Flourless birthday cake is disappointing. ⁢ are all flours forbidden for you? I looked it up, and rice and corn flour are sometimes permitted. I’ve had some very good rice flour cakes. [Next page](https://boards.straightdope.com/t/does-the-date-of-easter-favor-some-dates-over-others/1017173.md?page=2)