Day of the Week Calculator
Find out what day of the week any date falls on — past, present, or future.
About Day of the Week Calculator
This day of the week calculator uses Zeller's congruence algorithm to determine the day of the week for any given date. It works for dates in the past, present, and future, and provides additional information like the day number of the year, ISO week number, and the number of days until the same day of the week next occurs. Perfect for historical research, event planning, or satisfying your curiosity about what day a special date falls on.
Any Date, Any Year
Works for any date across the Gregorian calendar — past, present, or future — with accurate results every time.
Zeller's Algorithm
Uses the mathematically proven Zeller's congruence formula, the standard method for calculating days of the week.
Week Number
Shows the ISO week number and day of the year for any date, adding useful context to your query.
Historical Dates
Perfect for historians, genealogists, and anyone curious about what day of the week historical events occurred on.