An observance with no fixed date — it moves, and the range can be five weeks.
A moveable feast is an observance whose date is computed rather than fixed. Easter and everything hung off it are the familiar cases; so is every festival on a lunar or lunisolar calendar.
The phrase has passed into ordinary English to mean anything unpredictable, which slightly undersells it. These dates are entirely predictable — they are computed by rule, sometimes centuries ahead. What they are not is FIXED, and that is a different thing.
This is the category that makes a stored list of dates go stale. A fixed-date holiday copied from last year is right; a moveable one copied from last year is wrong, and nothing about the copy indicates which it was.
Both are computed from Easter rather than fixed to a date, and both move by weeks between years.
| 🇦🇩 | Friday 26 March 2027Andorra | Good FridayEaster minus 2. Western Easter 2027 falls on 28 March. |
| 🇧🇬 | Friday 30 April 2027Bulgaria | Good FridayThe same feast, the same offset, five weeks later — Orthodox computus. |
Computus is the specific calculation for Easter. Moveable feast is the general category of dates that are computed rather than fixed.
The opposite case. A fixed-date holiday is on the same calendar date every year; a moveable one is not.
See also computus · fixed date rule · relative to easter · lunisolar calendar
We hold this as any rule_type other than fixed_date. See what we hold.