Born on February 29: how does age work in a non-leap year?
A leap-day birthday needs an explicit convention. The calculator’s calendar comparison is not a statement of every jurisdiction’s legal age rules.
Age calculator →What this calculator returns
For a birth date of 2000-02-29, this site returns 25 completed years on 2026-02-28 and 26 on 2026-03-01. That follows its month-and-day comparison algorithm. It does not assert that every country recognizes a legal age threshold on March 1. The intended use of the age matters as much as the arithmetic.
Why another answer may appear
There is no February 29 in a non-leap-year calendar. Personal celebrations or particular administrative policies may choose February 28 or March 1. A celebration date does not necessarily determine a legal entitlement. Two sites can therefore disagree because they implement different conventions, rather than because one has failed to subtract correctly.
Check the calendar and the applicable rule
In the Gregorian calendar, years divisible by four are generally leap years, except century years must also be divisible by 400. Thus 2000 is a leap year and 2100 is not. For contracts, insurance, school enrollment or legal matters, consult the applicable rule rather than treating a general calculator as authority. For ordinary anniversary planning, agree on the convention first and record it with the result.
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