Age calculator
Find an age in years, months, and days from a birth date and an optional as-of date.
Short answer
Count full years from the birth date to the date you care about, then the leftover months, then the leftover days. Leave the second date blank to use today.
How this works
If the day you picked is earlier in the month than the birth day, that month is not finished and a month is borrowed. If the month is earlier than the birth month, the year is not finished either.
February 29 is a real day only in leap years. The calculator rejects dates that do not exist. It does not estimate a medical or legal age for a form that has its own rule.
Examples
Born 15 March 2000, as of 14 March 2026
25 years, 11 months, and 27 days. The 26th birthday is the next day.
Common mistakes
- Reporting the year subtraction even when the birthday is still ahead.
Frequently asked questions
- Which time zone is “today”?
- Today is the date on the clock of the computer answering the request. Pass an as-of date when the day matters.
Related
- How to calculate age from a birth dateCount finished years, then finished months, then days, and do not stop at a simple year subtraction.
- Days between datesCount the days between two calendar dates, including neither extra day beyond the span you picked.
- How to count days between two datesCount calendar days between two dates without losing or double-counting the day a month changes.