Work out an exact age in years, months and days from a date of birth, plus totals in weeks, days and hours and the countdown to the next birthday.
Age in whole years is easy. Age as an exact number of years, months and days is not, because months vary in length and leap years move the goalposts. This works it out precisely from a date of birth.
You also get the totals — months, weeks, days, hours and minutes lived — the weekday you were born on, and how long until the next birthday.
The method is the everyday one: count the completed years first, then the completed months since that anniversary, then the leftover days. You turn a year older on your birthday, not on any fractional average, and someone born on 15 May 2000 is 25 on 15 May 2025 regardless of how many leap years fell in between.
This matters because a naive calculation — total days divided by 365.25 — drifts by a day or more and can report the wrong age around a birthday. Counting whole calendar units avoids that entirely.
Someone born on 29 February has a birthday that exists only every fourth year. This page treats 28 February as the anniversary in non-leap years, which is the common convention and matches how most legal systems handle it in practice. Jurisdictions do differ — some treat 1 March as the day a legal age is attained — so for anything with legal consequence, check local rules rather than relying on any calculator.
The second field defaults to today but takes any date, which answers a different set of questions: how old someone will be at a wedding, whether a child meets a school cut-off, someone's age at a historical event, or age on a policy start date. Set it to a future date to project forward, or a past one to look back.
By counting completed calendar years, then completed months, then leftover days from your date of birth to the target date. That is the everyday definition, and it avoids the off-by-one errors of dividing total days by 365.25.
The anniversary falls on 28 February in non-leap years, the usual convention. Some legal systems use 1 March for attaining an age, so check local rules where it actually matters.
Yes. The second date field defaults to today but accepts any date, so you can work out an age at a future event or at a point in the past.
Totals are computed from whole days, since a time of birth is rarely known to the minute. The hours figure is therefore days multiplied by 24, not a to-the-second count.
Yes. Counting calendar units means leap days are naturally included in the day totals, and the century rules are applied — 1900 was not a leap year, 2000 was.