Enter a date of birth and this tool tells you how many days until your next birthday, the age you will turn, and which day of the week that birthday lands on. It is handy for planning parties, booking time off or simply satisfying curiosity.
How it works
The tool takes today’s local date at midnight and builds a candidate birthday using your birth month and day in the current year. If that date has already passed, it rolls forward to the same date next year. The countdown is then the number of whole days between today and that next birthday:
days = (next birthday − today) ÷ 24 hours
The age you will turn is simply the year of the next birthday minus your birth year, and the weekday is read directly from that date. For a 29 February birthday in a non-leap year, the tool falls back to 28 February as the closest matching day.
Example
Suppose today is 30 May 2026 and your birth date is 15 June 2000. Your birthday this year has not yet passed, so the next birthday is 15 June 2026:
| Result | Value |
|---|---|
| Days to go | 16 |
| Age turning | 26 |
| Falls on | Monday |
If today were the birthday, the tool would celebrate instead of counting.
It runs entirely in your browser — your birth date never leaves your device.