How is exact age calculated?
Subtract the birth year from the current year, then subtract 1 if this year's birthday hasn't happened yet. The remainder is counted forward in whole months and then days, which is why the answer isn't simply days ÷ 365.
Calculate your exact age in years, months, days, hours, and minutes from your date of birth. Also see your next birthday countdown.
Age = (today − date of birth), counted as completed years, then remaining months, then remaining days — not as total days ÷ 365.25.
Born 14 March 1990, measured on 27 July 2026: 36 completed years (last birthday 14 March 2026), plus 4 months and 13 days — so 36 years, 4 months, 13 days, or 13,284 total days.
Subtract the birth year from the current year, then subtract 1 if this year's birthday hasn't happened yet. The remainder is counted forward in whole months and then days, which is why the answer isn't simply days ÷ 365.
Calendar-date arithmetic absorbs leap days automatically. Someone born 29 February is treated as having a 28 February (or 1 March, depending on jurisdiction) birthday in common years.
Some tools count inclusive days (adding one for the birth day), and some ignore time zones. A one-day difference almost always comes from one of those two conventions.
Traditional East Asian reckoning starts a newborn at 1 and adds a year on New Year's Day, so it can be 1–2 years higher than international age. This calculator uses the international standard.
Set the target date instead of today. This is how insurers price 'age nearest birthday' and how schools apply cut-off dates for enrolment.