Age Calculator

Enter your date of birth and pick a unit: completed years, completed months, or days lived. Someone born on 15 March 1990 is 36 years old on 12 June 2026 — that is 434 months, or 13,238 days. The second field starts at today, so change it to ask about any other day.

Chronological age is the elapsed time between a date of birth and a reference day — the definition used in medicine, law and everyday life, as distinct from biological age or how old you feel. This calculator gives it in one unit at a time: completed years, completed months, or days lived. The naive approach divides total days by 365.25, which produces fractional years and ignores the shape of the calendar. This one counts whole calendar steps instead. A month ends on the same day number it started on, clamped to the length of the landing month, so 31 January plus one month lands on 28 February in a non-leap year. If the reference day falls before that clamped day, the month is not yet complete and is not counted. Whole years are then the completed months divided by twelve. Someone born on 15 March 1990 is 36 years old on 12 June 2026 — or 434 completed months, or 13,238 days lived. The caveat that matters most is that those three units are not rounded views of one another. Years and months both discard the remainder, so a person one day short of a birthday still reads as the year before. Days lived is a plain count, and it is the only one of the three that changes every morning.