Day of the week finder
Which weekday any date falls on.
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How it's calculated
Every date is a whole number of days from any fixed day, and days cycle through the week in sevens. Count the days from a known Monday, 5 January 1970, divide by seven and keep the remainder: 0 is a Monday, 1 a Tuesday, up to 6 for a Sunday. The tool adds one so Monday reads as day 1, and the name appears underneath. The same count against today gives how far away the date is.
What day of the week was I born?
Enter your birth date. The remainder trick works for any date after 1970; for earlier dates, the same method works from any other known Monday, which is how the Zeller and Doomsday mental methods do it by hand.
How can I work it out in my head?
John Conway's Doomsday rule: in any year, 4/4, 6/6, 8/8, 10/10 and 12/12, plus 5/9, 9/5, 7/11 and 11/7, all fall on the same weekday, the year's "doomsday". In 2026 it is Saturday. So 7/11/2026 is a Saturday, and July 4, exactly a week earlier, is a Saturday too. Learn the year's doomsday and count from the nearest anchor date.
Why does the calendar repeat every 28 years?
A normal year shifts the weekday by one, a leap year by two, so after 28 years (seven shifts of four-year leap cycles) the pattern returns. 2026 has the same calendar as 1998 and 2054, except across century years that skip the leap day.
Results are estimates for informational purposes only and are not financial, medical or legal advice.