Age Calculator
An age calculator works out the time between a date of birth and today in years, months and days. It also shows your age in total months and total days, and how many days remain until your next birthday.
Calculate your age
Age Calculator
How to use it
- Enter your date of birth as day, month and year.
- Select Calculate Age.
“Today” is taken from your device’s date, so check your device clock if a result looks a day off.
How age is calculated
The calculator counts complete years first, then complete months, then the remaining days. Months have different lengths, so “1 month” can be 28 to 31 days, and different calculators can differ by a day around month ends. Total days is an exact count of days between the two dates.
Leap-year birthdays
If you were born on 29 February, the next-birthday count uses 1 March in years without a 29 February.
Common uses
Checking eligibility ages for school, sport or exams, filling in forms that ask for age in years and months, and planning milestone birthdays.
Worked example
Born 15 June 1990, checked on 4 October 2026: from 15 June 1990 to 15 June 2026 is 36 complete years; to 15 September is 3 more complete months; 15 September to 4 October is 19 days. Age: 36 years, 3 months, 19 days.
Age in different systems
Most countries count age from birth, starting at zero. Some traditional systems differ. For example, the traditional Korean count started at one and added a year each new year, though South Korea standardised official use on the international system in 2023. Forms usually want the international count shown here.
Frequently asked questions
It’s designed for realistic birth dates. Very old or future dates are rejected with a message.
Dates such as 31 February or 29 February in a non-leap year don’t exist, so the calculator asks you to correct them.
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