How it works
Subtract the birth year from the reference year, then subtract one if the birthday is still ahead in the reference year. The reference date is editable; the initial date is a worked example.
Worked example
Show example inputs and result
Date of birth: May 15, 1995 · Age on this date: October 8, 2026.
- Completed years
- 31
- Total days
- 11,469
Questions and answers
How are February 29 birthdays handled?
In a non-leap year, this calculator increases the completed age on March 1. This is a stated calculation convention, not a determination of legal age rules.
Why are some results rounded?
Results display up to 8 decimal places. Calculations use the unrounded values; very small values use scientific notation. JavaScript floating-point arithmetic can introduce tiny rounding differences.
Are my inputs sent to a server?
The calculator processes inputs in your browser. Its code does not send your values to a server.
Method reviewed: October 8, 2026 · Methods & accuracy