Current for 2026•As of: July 2026

Day of the Week Calculator What day was ...?.

Find the day of the week for any date in seconds

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Day of the Week Calculator

Find the day of the week for any date – instantly and free.

Please enter a date

Day of the week calculator: Monday to Sunday for any date

UTC-accurate calculation without the daylight saving bug

The day of the week calculator instantly returns the weekday name for any date you enter – from Monday to Sunday. The calculation is UTC-based, which means that daylight saving time changes (DST) have no effect on the result. Leap years are automatically handled correctly.

Typical use cases: What day of the week was my birthday? What day of the week does Christmas 2030 fall on? Was September 1, 1939 a Friday? (Yes, it was.) The calculator works for dates from antiquity far into the future.

Frequently asked questions about the day of the week calculator

Algorithms, leap years and UTC explained

There are several methods: the easiest is to use a digital calculator like ours. Mathematically, the day of the week can be calculated with the Zeller congruence or the Doomsday algorithm. Our calculator uses UTC-based JavaScript date processing for maximum precision.

Without UTC-based calculation, daylight saving time (DST) changes in certain time zones can lead to an incorrect result. With UTC, dates are always treated correctly as pure calendar dates, independent of the local time zone.

January 1, 2000 was a Saturday. You can enter this or any other date into our calculator and see the result instantly.

Yes. Leap years (divisible by 4, except by 100 – unless divisible by 400) are automatically taken into account correctly in the calculation. For example, February 29, 2024 was a Thursday.

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Calculators for your website or app

Integrate our GDPR-compliant calculators as a widget or use our API. Perfect for HR portals, career pages and financial applications.

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  • ✓REST API for your own applications
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