"How old are you?" sounds like a one-number question until someone asks for the exact figure — years, months and days — for a form, an insurance quote or a milestone birthday. Doing it by hand means borrowing months and juggling leap years, which is exactly the kind of arithmetic humans get wrong.
This calculator does the calendar math properly: it counts full years and months from the birth date to today (or any date you choose), handles leap years and varying month lengths, and also shows the totals — total months, weeks, days, hours — that are handy for trivia, announcements and paperwork. It even counts down to the next birthday.
Part of the Everyday Calculators collection on CountCrunch.
How exact age is calculated
The calculator finds the difference between the two dates in calendar terms, borrowing from months and years exactly as the calendar does:
Example: born 15 March 1990, measured on 10 October 2026 → 36 years, 6 months, 25 days. Leap-day babies (29 February) are handled: in non-leap years the birthday is counted on 28 February for age purposes.
Everything on the results panel
- Exact age: years, months and days — the figure forms ask for.
- Totals: age in total months, weeks, days, hours and minutes.
- Next birthday: days remaining and the weekday it falls on.
- Day of birth: the weekday you were born on.
Frequently asked questions
How do I calculate my exact age?
Count full years from your birth date, then full months since your last birthday, then remaining days. The calculator above does the borrowing and leap-year handling for you.
How old will I be on a future date?
Change the "as of" date to any future date and the calculator gives the exact age on that day — handy for eligibility cutoffs and retirement planning.
What day of the week was I born?
Enter your birth date and the results panel shows the weekday. It is also fun for anniversary trivia.
How are leap-year birthdays handled?
Someone born on 29 February ages normally in leap years. In common years most legal systems treat 28 February (some use 1 March) as the birthday for age purposes; the calculator counts from 28 February.