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Age Calculator
Calculate age in years, months, and days from a birth date.
Free to use — no sign-up or login.
Result
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Age is usually stated as the number of birthdays you have completed, but a useful age calculation can also show the remaining months and days. Enter a birth date and choose the date you want to calculate age on. The result separates completed calendar years, months, and days rather than merely dividing elapsed days by 365.
The as-of date matters: you can check someone's age today or on another date, such as an upcoming birthday. The calculator works with calendar dates, not times of day, so it is designed for ordinary age and date questions rather than hour-by-hour elapsed time. To shift a calendar date by a number of days, use the Date Calculator. For a readout that keeps ticking, use the Live Age Calculator.
Why the birthday changes the year count
Someone born on 10 June 2000 is 25 years old on 9 June 2026 and turns 26 on 10 June 2026. A simple subtraction of year numbers would report 26 on both dates, but that ignores whether the birthday has occurred. The age calculator counts full years first and then the remaining calendar months and days.
Calendar months are not all the same length
A calendar month is not a fixed number of days: February can have 28 or 29 days, while other months have 30 or 31. For this reason, age in years, months, and days is not obtained by dividing a total day count into fixed 30-day months. When interpreting unusual dates such as 29 February birthdays or month-end boundaries, check the actual dates displayed in the calculator.
Worked example: birthday as-of date
Birth date 10 June 2000; as-of 10 June 2026: 26 years, 0 months, 0 days.
\[ 2000\text{-}06\text{-}10 \to 2026\text{-}06\text{-}10 \]
Worked example: day before the birthday
Birth date 10 June 2000; as-of 9 June 2026: 25 years, 11 months, 30 days.
\[ 2000\text{-}06\text{-}10 \to 2026\text{-}06\text{-}09 \]
Frequently asked questions
Can I calculate age on a date other than today?
Yes. Enter your chosen date in the As of field to calculate calendar age on that date.
Why isn't age just the difference between the two year numbers?
That subtraction ignores the birthday. Full years count only after the corresponding birthday has occurred.
Does this calculator show total hours or minutes lived?
No. It reports calendar years, months, and days, using date inputs rather than birth times.
How does a leap-day birthday affect age?
The calculation uses calendar dates, including leap years. For a 29 February birthday in a non-leap year, conventions about which day counts as the legal birthday can vary. Do not use this tool to make legal age determinations.
References
Assumptions and limitations
The as-of date must not precede the birth date. Results are calendar-date calculations without time of day, time zones for birth events, or jurisdiction-specific legal birthday rules. The calculator is informational, not an official age or identity verification service.