Find which day of the week any date falls on — past, present or future — plus the day of the year and ISO week.
Enter the date and read the weekday. For example, 15 August 1947 was a Friday and 26 January 1950 was a Thursday. The tool uses the Gregorian calendar, so it works for any year from 1 to 9999.
Type any date and this calculator tells you the day of the week, the day number within the year, how many days remain in the year, the ISO week number, and whether it is a leap year. A second tool finds a date by rule — such as the second Tuesday of March or the last Monday of May — which is how many holidays and events are defined.
Use it to check what day you were born, find the weekday of a historical event, plan a future date, or work out when a recurring meeting falls. For the days between two dates use the Date Calculator or the Day Counter.
The tool counts days from a fixed reference date and takes the remainder when divided by 7, the same idea as the classic Zeller and Doomsday methods.
| Date or question | Answer |
|---|---|
| 15 August 1947 (India's Independence Day) | Friday |
| 26 January 1950 (first Republic Day) | Thursday |
| 1 January 2000 | Saturday |
| 25 December 2026 | Friday |
| Second Tuesday of March 2026 | Tuesday, 10 March 2026 |
| Fourth Thursday of November 2026 | Thursday, 26 November 2026 |
The Gregorian calendar was introduced in 1582 and adds a leap day every four years, skipping century years unless divisible by 400. This keeps the calendar aligned with the seasons to within about one day in 3,000 years. A normal year has 365 days — 52 weeks plus one day — which is why a date moves forward one weekday each year, and two weekdays after a leap day.
Enter the date in the first calculator. It works out the weekday from the number of days since a reference date, taking the remainder when divided by 7.
Enter your date of birth to see the weekday. For example, 1 January 2000 was a Saturday.
Yes, for any year from 1 to 9999 using the Gregorian calendar rules projected backwards. Historical dates before the calendar was adopted in your region may have been recorded differently.
ISO 8601 numbers weeks from Monday, and week 1 is the week that contains the year's first Thursday. Some years have 53 ISO weeks, and early-January dates can belong to the previous year's last week.
It is a leap year if divisible by 4, except century years, which must be divisible by 400. So 2000 and 2024 were leap years; 1900 and 2100 are not.
Use the second calculator: pick which one (first to fourth, or last), the weekday, the month and the year.
A year has 365 days, which is 52 weeks plus 1 day, so the same date moves forward one weekday each year (two after a leap day).
Enter it in the calculator — it is a Friday.
It is the position of the date within the year, from 1 on 1 January to 365 (or 366) on 31 December.
No. All calculations run in your browser.
