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Birth Day of the Week Calculator

Find the weekday you were born on, the weekday of your next birthdays, which weekdays repeat most, and the Doomsday rule behind it.

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Day of the week calculatorFind out which day of the week any date falls on.Day of the Year CalculatorThe ordinal day number of any date — the ISO 8601 ordinal format — with the days remaining, the ISO week, the quarter, the weekday, the percentage of the year elapsed, and the month-by-month addition shown in full.Day of Year CalendarA full year on one page: twelve month blocks where every cell carries its day-of-year number from 1 to 365 or 366, today highlighted, and each date's ISO week, quarter and days remaining one click away.First Day of Autumn CalculatorThe exact instant autumn begins — September equinox in the north, March equinox in the south — and how many minutes of daylight your latitude loses each day at that moment, the fastest rate of the year.First Day of Spring CalculatorThe exact instant spring begins in either hemisphere — March equinox in the north, September equinox in the south — in UTC and in your own offset, with the astronomical and meteorological start side by side and the next ten years.First Day of Summer CalculatorThe exact instant summer begins — June solstice in the north, December solstice in the south — plus the latitude above which the Sun never sets and why summer is the longest astronomical season.First Day of Winter CalculatorThe exact instant winter begins — December solstice in the north, June solstice in the south — why it is the shortest astronomical season, and why meteorological winter straddles two calendar years.Is It April Fools' Day? CalculatorA straight yes or no, a live countdown to 1 April, the weekday it falls on for the next ten years and how the prank tradition differs from France to Iran.

Open Birth Day of the Week Calculator and you get an answer straight away, with no account to create. You will find it under Dates & time, with Day of the week calculator and Day of the Year Calculator for the neighbouring cases.

How to use it

  1. Open the tool — no signup or install needed.
  2. Enter your input or adjust the available options.
  3. Get your result instantly, then copy or download it.

Frequently asked questions

What is Birth Day of the Week Calculator?

Find the weekday you were born on, the weekday of your next birthdays, which weekdays repeat most, and the Doomsday rule behind it.

When would I actually use this?

Answering a scheduling question exactly: how many working days until a deadline, what date falls sixty days out, and what time that is for a colleague elsewhere.

What is the most common mistake?

Counting days by subtracting dates and forgetting whether the endpoints are included. Inclusive and exclusive counts differ by one, which is the difference between meeting a deadline and missing it.

How is Birth Day of the Week Calculator different from Day of the week calculator?

They sit next to each other but answer different questions: Day of the week calculator is the one to open when you need it to find out which day of the week any date falls on. Pick whichever matches what you're starting from — both are free.

Is there a tool for the next step?

Day of the Year Calculator is the closest one after this: The ordinal day number of any date — the ISO 8601 ordinal format — with the days remaining, the ISO week, the quarter, the weekday, the percentage of the year elapsed, and the month-by-month addition shown in full.

What else is worth having open alongside it?

Day of Year Calendar and First Day of Autumn Calculator — they come up in the same task often enough to be worth a second tab.

Where do the figures come from?

Calendar arithmetic follows the proleptic Gregorian calendar and the IANA time-zone database, so daylight-saving transitions and leap years are handled. Public holidays vary by country and region and are not assumed.

Further reading

All guides →
How-toWhat Day of the Week Was I Born? Find Out in SecondsFind the weekday of any birth date. Learn the quick calculator method and a short introduction to the Doomsday rule for working it out in your head.ExplainerWhat Generation Am I? Birth-Year Cutoffs ExplainedBoomer, Gen X, Millennial, Gen Z or Alpha? Learn the commonly used birth-year ranges, why the boundaries are fuzzy, and how to place yourself if you were born near a cutoff.How-toHow to Convert Time Zones: UTC Offsets, Day Rollover and DSTConverting between time zones is adding or subtracting the difference in UTC offsets, then handling any day rollover. Learn the method, a worked example, and the DST caveat.ExplainerHow Daylight Saving Time Works: Spring Forward, Fall BackDaylight saving time shifts clocks an hour in spring and back in autumn. Learn spring-forward and fall-back, why one day is 23 hours and another 25, and how US and EU dates differ.How-toHow Many Days Have I Been Alive? Count Days, Weeks and MonthsYour age in days is the whole number of days between your birth date and today. Learn how to count it by hand, convert it to weeks and months, and why leap years matter.How-toCountdown to New Year: How to Count the Days and Weeks LeftBuilding a countdown to a target date is just counting whole days from today to the target, then splitting that total into weeks. Learn the method with a worked example.