Enter any date — day, month, and year — and the Weekday Calculator tells you exactly what day of the week it falls on. You'll also see the day number of the year, how many days remain in that year, and whether it's a leap year. Great for planning events, checking historical dates, or satisfying curiosity about any date from the past or future.
Day of the Week
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Full Date
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Day Number of the Year
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Days Remaining in Year
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Leap Year?
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Week Number of Year
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The calculator uses JavaScript's built-in Date object, which implements the proleptic Gregorian calendar. Given a day, month, and year, it constructs the date and calls getDay() to retrieve the weekday index (0 = Sunday through 6 = Saturday). This method is accurate for any valid date within the supported year range.
The day number of the year (also called the ordinal date) tells you which day out of 365 (or 366 in a leap year) a specific date falls on. For example, February 1st is day 32. It's calculated by counting all elapsed days from January 1st up to and including the date in question.
A leap year occurs every 4 years to keep our calendar aligned with Earth's orbit around the sun. A year is a leap year if it is divisible by 4, except for century years (e.g. 1900), which must be divisible by 400. So 2000 was a leap year, but 1900 was not. The calculator automatically tells you whether the entered year is a leap year.
The Weekday Calculator supports any date from year 1 through year 9999. Keep in mind that for dates before October 15, 1582, the Gregorian calendar was not yet adopted in most of the world — the Julian calendar was in use. The calculator applies the Gregorian system throughout, known as the proleptic Gregorian calendar.
The seven day names in English derive from a mix of Roman and Norse/Germanic traditions. Sunday and Monday are named after the Sun and Moon. Tuesday through Friday honor Norse gods (Tyr, Woden, Thor, Frigg), while Saturday comes from the Roman god Saturn. This naming system spread across Europe with the Roman calendar.
Easter is a moveable feast calculated based on the lunar calendar. It falls on the first Sunday after the first full moon that occurs on or after the spring equinox (March 21). Because the lunar cycle doesn't align perfectly with the solar calendar, the date shifts each year, ranging anywhere from March 22 to April 25.
The ISO week number indicates which week of the year a date belongs to, with weeks starting on Monday. Week 1 is the week containing the first Thursday of January. A year can have 52 or 53 ISO weeks. This system is widely used in business and project scheduling.
Absolutely. Just enter your birth date — day, month, and year — and the calculator will tell you exactly which day of the week you were born on. Many people are surprised to discover the day of their birth, and it's a fun fact to share.