Age Calculator
Find your exact age in years, months and days from any date.
About this calculator
An age calculator gives you the exact distance between two dates — usually a birthday and today. It’s useful for filling in forms that need a precise age, for retirement and pension planning, or simply for fun calculations like how many days old someone is.
How it works
The calculator counts whole years between the two dates, then whole months in the partial year, then the remaining days. Leap years and varying month lengths are handled correctly so the result matches what a human would write on a passport or visa form.
It also returns the total in months and the total in days, which is useful for younger children where age is more naturally expressed in months, and for any context where you need a single integer for comparison.
If the target date is before the start date the calculator reports an error rather than producing a negative age. This avoids accidental nonsense answers when fields are filled in the wrong order.
Time zones aren’t considered. Age is a civil concept tied to the calendar in your locale — the calculator uses the date as you entered it and never converts.
Formula
years = to.year − from.year (− 1 if month/day rolled back)
months = to.month − from.month (+ 12 if rolled back)
days = to.day − from.day (+ days-in-previous-month if rolled back)Examples
Born 2000-01-01, today 2026-05-22
Someone born on the first day of the century is 26 years, 4 months and 21 days old as of 22 May 2026.
Result: 26 years, 4 months, 21 days — 9,638 total days
Across a leap-year boundary
Because 2026 has no 29 February, the calculator recognises that 28 February 2026 is one day shy of a full second year.
Result: 1 year, 11 months, 30 days