Age & next birthday
Calculate completed age, days since birth and the next birthday using today or another reference date. Files and entered content are not sent to or stored on a server.
How to use
Calculate completed age, days since birth and the next birthday using today or another reference date.
Please note
For February 29 births, March 1 is the default in non-leap years; February 28 can be selected instead. The same rule applies to the displayed age.
Age & next birthday User guide
Instructions
- Enter a birth date.
- Use today or choose a reference date. For February 29 births, choose the non-leap-year birthday rule.
- Check the age in completed years and the next birthday, then copy the result if needed.
Example
Input / settings
Born 2000-10-15 · reference 2026-10-14
Result / checks
Age 25 · birthday in 1 day
Please note
- For February 29 births, March 1 is the default in non-leap years; February 28 can be selected instead. The same rule applies to the displayed age.
- Birth and reference dates are saved only in this browser. A reference date before birth is rejected.