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Find out what day of the week any date falls on, plus the day of the year.
Zeller's Algorithm (simplified):
JavaScript Date.getDay() returns 0 (Sun) through 6 (Sat)
The date is parsed and the built-in getDay() method returns the day index. The calendar offset is set to noon to avoid DST boundary issues.
January 1, 2000 was a Saturday. Enter the date to confirm with this calculator.
JavaScript's Date object supports dates back to 100 million days before January 1, 1970. For very ancient dates, the Gregorian calendar proleptic extension is used.
Setting the time to 12:00:00 avoids Daylight Saving Time boundary issues. A date at midnight can shift to the previous day in some time zones during DST transitions.
The day of the year is the ordinal position of the date within the calendar year. January 1 is day 1, December 31 is day 365 (or 366 in leap years).
Yes. Enter any future date and the calculator will display the day of the week it falls on.