About the Birthday Countdown Calculator
Days until your next birthday, the age you will turn and what day it falls on.
Also known as: days until my birthday, birthday counter, how long until my birthday, next birthday.
How to use this calculator
- Enter date of birth, today.
- The result updates instantly as you type — press Calculate (or Enter) at any time.
- Review the breakdown shown under the main result.
- Use Copy result or Share to save the answer or send a link with your inputs.
Formula
days = next birthday − today
Worked example
Using the values pre-filled in the calculator above:
- Date of birth: 1990-06-15
- Today: 2026-09-22
the calculator returns:
- Days to go: 266
- Next birthday: Tuesday, June 15, 2027
- Turning: 37
- Day of the week: Tuesday