About the Day of Week Finder
What is the Day of Week Finder?
Want to know what day you were born on, or which day a festival falls? This day of week finder works for any date in the Gregorian calendar.
It also gives the day number within the year, the ISO week and the quarter.
How to use the Day of Week Finder
- Date (sample: 23 Oct 2026)
- Press Find the Day (results also refresh as you type). The result card shows the Day of Week, along with Date, Day of the year, ISO week and Quarter.
Formula used
Weekday = (days since a known reference date) mod 7
The Gregorian calendar repeats exactly every 400 years.
Worked example
These are the sample values already filled in the calculator above, and the result it returns for them:
| Input | Sample value |
|---|---|
| Date | 23 Oct 2026 |
| Result | Value |
|---|---|
| Day of Week | Friday |
| Date | 23 October 2026 |
| Day of the year | 296 |
| ISO week | Week 43 of 2026 |
| Quarter | Q4 |
| Leap year | No |
| From today | Today |
Tips for using the Day of Week Finder
- India's Independence Day, 15 August 1947, was a Friday.
- A date falls on the same weekday again after 5, 6 or 11 years, depending on leap years.