Easter Calculator
Calculate the date of Easter Sunday for any year. Easter is calculated using the Computus algorithm based on the lunar calendar.
1583-4099 (Gregorian calendar)
Easter Sunday
Sunday, April 20, 2025
Good Friday
Friday, April 18, 2025
Easter Monday
Monday, April 21, 2025
How to Use This Calculator
- Enter the year (1583-4099, Gregorian calendar range).
- The calculator displays Easter Sunday date for that year.
- It also shows Good Friday (2 days before) and Easter Monday (1 day after).
- Use this to plan holidays, events, or understand when Easter falls each year.
Easter Date Formula (Computus)
Easter is calculated using the Computus algorithm with multiple steps:
b = floor(year / 100)
c = year % 100
d = floor(b / 4)
e = b % 4
f = floor((b + 8) / 25)
g = floor((b - f + 1) / 3)
h = (19a + b - d - g + 15) % 30
i = floor(c / 4)
k = c % 4
l = (32 + 2e + 2i - h - k) % 7
m = floor((a + 11h + 22l) / 451)
month = floor((h + l - 7m + 114) / 31)
day = ((h + l - 7m + 114) % 31) + 1
Example: Year 2024: Easter Sunday = March 31, 2024. Good Friday = March 29, 2024. Easter Monday = April 1, 2024. The algorithm ensures Easter falls on the first Sunday after the first full moon following March 21.
Full Description
Easter is a moveable feast, meaning its date changes each year. The date is determined by the Computus algorithm, which calculates Easter based on the lunar calendar and vernal equinox. Easter falls on the first Sunday after the first full moon following March 21 (the vernal equinox). This ensures Easter aligns with both solar and lunar cycles.
The Computus algorithm uses several calculations involving the year, lunar cycles (Golden Number), and day of week calculations. The result is the date of Easter Sunday, which can occur anywhere from March 22 to April 25. Good Friday (the Friday before Easter) and Easter Monday (the day after) are also calculated based on the Easter date. The algorithm works for years 1583-4099 in the Gregorian calendar.
This calculator helps you determine Easter dates for any year. Enter a year, and it calculates Easter Sunday, Good Friday, and Easter Monday. Use it to plan holidays, schedule events, understand the Easter calendar, or simply find when Easter falls in any year. The Computus algorithm ensures accurate Easter dates based on astronomical calculations!
Frequently Asked Questions
How is Easter date calculated?
Easter is calculated using the Computus algorithm: Easter falls on the first Sunday after the first full moon following the vernal equinox (March 21). The calculation uses lunar cycles and the Gregorian calendar. This is why Easter dates vary each year.
Why does Easter date change every year?
Easter is tied to the lunar calendar (full moon) and solar calendar (vernal equinox). Since lunar months don't align perfectly with solar years, Easter dates shift. Easter can occur between March 22 and April 25 in the Gregorian calendar.
What is the Computus algorithm?
Computus is the calculation method for determining Easter date. It uses: Golden Number (lunar cycle), Epact (age of moon), and Dominical Letter (day of week). The algorithm accounts for lunar and solar cycles to find the correct Easter Sunday.
What are Good Friday and Easter Monday?
Good Friday is the Friday before Easter Sunday (2 days before), commemorating the crucifixion. Easter Monday is the day after Easter Sunday (1 day after), a holiday in many countries. The calculator shows both dates based on the calculated Easter date.