Age Calculator
Calculate calendar age, total days and the next birthday. Save birthdays locally if you choose.
Ready when you are
Saved birthdays
For February 29 birthdays, this tool uses March 1 in non-leap years. This is a calendar preference, not a legal age assessment.
How to use
- Enter the birth date and calculation date.
- Read calendar age and the next birthday.
- Optionally save locally and export JSON or birthday ICS.
A few things to know
For February 29 birthdays, this tool uses March 1 in non-leap years. This is a calendar preference, not a legal age assessment.
Month additions clamp to the last day: January 31 + one month is the last day of February. Calendar days do not assume 24 hours.
Questions and answers
How are February 29 birthdays handled?
For February 29 birthdays, this tool uses March 1 in non-leap years. This is a calendar preference, not a legal age assessment.
Technical references: Calendar date arithmetic (Temporal)
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