How to Use Easter Calculator
Type the year you want to check, such as 2027 or 2035. The Easter Calculator runs the full Meeus/Jones/Butcher sequence in the browser and returns the Easter Sunday date, month number, day number, and weekday.
Use years 1583 or later when you want the Gregorian Western date. If you are preparing a church calendar, school schedule, or holiday plan, confirm whether the organization follows Western Gregorian Easter or a different liturgical calendar before relying on the result.
Formula & Theory - Easter Calculator
The calculator follows the Meeus/Jones/Butcher algorithm, a compact modular arithmetic method for Gregorian Easter:
a = Y mod 19
b = floor(Y / 100), c = Y mod 100
h = (19a + b - floor(b/4) - g + 15) mod 30
l = (32 + 2e + 2i - h - k) mod 7
month = floor((h + l - 7m + 114) / 31)
day = ((h + l - 7m + 114) mod 31) + 1The algorithm approximates the ecclesiastical full moon rule used to set Easter as the Sunday after the Paschal full moon. The output is deterministic for a given year, but it represents the Western Gregorian convention rather than every Christian tradition.
Use Cases for Easter Calculator
- School calendars - Find Easter break timing when planning spring terms or exam periods.
- Church scheduling - Check the date before arranging services, choir rehearsals, or volunteer calendars.
- Calendar programming - Use a known algorithm to test date-handling code and modular arithmetic.
The result is exact for the selected Gregorian rule, but the correct calendar tradition matters when comparing across countries or denominations.