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Leap-day birthdays and civil age
How Long Until editorial · 2026-06-09
People born on 29 February still age one year per year. This site observes the birthday on 28 February in common years.
A leap-day birthday exists four times a decade, roughly. Age still increases every year. The open question is which civil date counts as the birthday when February has 28 days.
Jurisdictions differ. This site’s age calculator treats 28 February as the observed birthday in common years. On that date the completed-year count increases. In leap years the observed date is 29 February.
The calculator does not decide legal majority, visa rules, or school cutoffs. Those depend on local law. It only reports a consistent calendar age: years, leftover months, leftover days, and total days between two valid dates.