Everyday Tools
29 February handled

Age calculator: years, months and days

Find an exact age on any date, not just today. Enter a date of birth and the calculator gives the age in whole years plus months and days, how long until the next birthday and which day of the week it falls on, and the total number of days lived so far. It's handy for forms that ask for age on a particular date, school and sports age groups, or simply settling who is older.

Dates

Age
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Next birthday
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Days aliveincluding leap days
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How an age is counted

Age in years goes up by one on each birthday, so the calculator first finds the most recent birthday on or before the "age on" date. The months and days are then counted from that birthday: whole calendar months first, then the days left over. If a month would land on a date that doesn't exist, such as the 31st of a 30-day month, it uses the last day of that month, the same rule used when adding months to a date.

The days-alive figure is a straight count of calendar days between the two dates, so it includes every leap day that has passed.

Worked examples

  • Someone born on 15 June 1990 is 36 years, 3 months and 17 days old on 2 October 2026, and has lived 13,258 days. They turn 37 in 256 days.
  • A child born on 3 November 2019 is 6 on 2 October 2026, with 32 days to go until turning 7, useful for sports or school groups that set age by a cut-off date.
  • Someone born on 29 February 2008 is 18 on 28 February 2026 if birthdays in ordinary years are counted on 28 February, or 17 if they're counted on 1 March.

The 29 February question

People born on a leap day have a real birthday only once every four years, so in other years they pick a day to celebrate. Some choose 28 February, which keeps the birthday in the same month; others choose 1 March, the day after 28 February. The answer can matter for official purposes such as the date someone becomes old enough to do something, and different countries and organisations have their own rules. The calculator lets you choose, and shows the choice only when the date of birth is 29 February. For anything with legal weight, check the rule that applies to you rather than relying on this tool.

Mistakes to avoid

  • Subtracting years only. 2026 minus 1990 is 36, but someone born late in the year might still be 35. The birthday has to have passed.
  • Using today's date when a form asks for age on a set date, such as 1 January for an age group or the date of an event. Change the "age on" date.
  • Treating months as equal lengths. "Six months old" means six calendar months, not 180 days.

The dates you enter stay in your browser and aren't saved or added to the page address. To count the days between any two dates, use the days between dates calculator; to see a date in another time zone, try the time zone converter.

Questions people ask

How do I work out an age on a past or future date?

Change the "Age on" date. It starts at today but can be any date after the date of birth.

Why does my age in days not equal years times 365?

Leap years add a day roughly every four years, and the partial year since the last birthday adds more. The calculator counts actual calendar days.

Last reviewed: