Work out easter date instantly with clear inputs, formula shown and shareable results.
This uses the anonymous Gregorian computus, an exact integer algorithm that returns Western Easter for any year from 1583 to 4099 without needing lunar tables. Easter is the first Sunday after the ecclesiastical full moon on or after 21 March, which is why it moves across a 35 day window from 22 March to 25 April.
Computus
a = year mod 19; h = (19a + b - d - g + 15) mod 30; month and day follow from h, l and m
a = year mod 19; h = (19a + b - d - g + 15) mod 30; month and day follow from h, l and m. This uses the anonymous Gregorian computus, an exact integer algorithm that returns Western Easter for any year from 1583 to 4099 without needing lunar tables.
Easter is the first Sunday after the ecclesiastical full moon on or after 21 March, which is why it moves across a 35 day window from 22 March to 25 April.
Enter year, count from. The defaults shown are a realistic worked example — swap in your own figures to get a result you can use.