Day of the Week CalculatorFind the weekday of any date, and learn to do it in your head
Enter any past or future date to find what day of the week it falls on, with the day of the year, ISO week and a calendar view, plus a step-by-step Doomsday-method worksheet so you can check it by hand.
- Any date from year 1
- Doomsday worksheet
- Calendar repeat finder
- Julian-date warning
Day of the week calculator
That date falls on a
Sunday
Do it in your head: the Doomsday method, worked for your date
John Conway’s trick: every year, certain easy dates (4/4, 6/6, 8/8, 10/10, 12/12, the last day of February) all fall on the same weekday, the year’s “doomsday”. Find it, then count to your date.
What day of the week was a date?
Enter any date to see its weekday. The Apollo 11 Moon landing, July 20, 1969, was a Sunday, and December 25, 2026 is a Friday. To work it out without a calculator, use Conway’s Doomsday rule. Each century has an anchor day, the year’s last two digits shift it to that year’s “doomsday”, and memorable dates such as 4/4, 6/6, 8/8, 10/10 and 12/12 always fall on that doomsday. The worksheet above shows each step for your date.
Doomsday reference: month anchors
| Month | Doomsday date | Memory hook |
|---|---|---|
| January | 3 (4 in leap years) | “3 years out of 4 it’s the 3rd” |
| February | 28 (29 in leap years) | The last day of February |
| March | 14 | Pi Day (3/14) |
| April, June, Aug, Oct, Dec | 4/4, 6/6, 8/8, 10/10, 12/12 | Even months: the same number |
| May & September | 5/9 and 9/5 | “I work 9-to-5 at the 7-Eleven” |
| July & November | 7/11 and 11/7 | 7-Eleven, both ways |
What day is New Year’s and Christmas, 2024–2032
| Year | January 1 | December 25 | Leap year |
|---|---|---|---|
| 2024 | Monday | Wednesday | Yes |
| 2025 | Wednesday | Thursday | No |
| 2026 | Thursday | Friday | No |
| 2027 | Friday | Saturday | No |
| 2028 | Saturday | Monday | Yes |
| 2029 | Monday | Tuesday | No |
| 2030 | Tuesday | Wednesday | No |
| 2031 | Wednesday | Thursday | No |
| 2032 | Thursday | Saturday | Yes |
Related calculators
Weekday found. These calendar tools go further:
More Date & Countdown calculators in this cluster:
Manzoor Ahmad
Calculator Developer · Founder of DexoCalc
I’m a pharmacist turned web developer with 13+ years of experience building web tools. I added the Doomsday worksheet because a mental-math trick is more useful than an answer you have to take on trust. Each step is recomputed for your date and checked against the calendar engine.
Published · Last reviewed · Author profile · Report an issue
Day of the week: frequently asked questions
Enter your birth date and the weekday appears instantly. The birthday calculator also shows the weekdays of your next 10 birthdays.
With the Doomsday rule: find the century’s anchor day, add the year’s last two digits divided by 12 (quotient plus remainder) and the remainder divided by 4, which gives the year’s doomsday. Then count from the nearest month anchor such as 4/4 or 6/6. Zeller’s congruence is another formula that does the same thing.
A Sunday, the day Apollo 11 landed on the Moon. It’s the default example in the calculator.
It calculates any date in the proleptic Gregorian calendar. For dates before the Gregorian reform (1582, later in some countries), historical documents usually used the Julian calendar, so the weekday they record can differ.
Weekdays repeat every 400 years exactly (146,097 days is a whole number of weeks). A single year’s calendar repeats after 6, 11 or 28 years depending on leap years. The calculator lists the next years when your date falls on the same weekday.
Christmas Day 2026 is a Friday and Christmas 2027 is a Saturday. See the table for other years.
Sources & references
- Doomsday Method, Wolfram MathWorld
- The Gregorian Calendar, timeanddate.com
- ISO 8601: Date and time format, International Organization for Standardization
Weekdays are given in the Gregorian calendar, extended backward for early dates.