Calculators

Age Calculator

Work out an exact age in years, months and days — and how long until the next birthday.

Change this to measure the gap between any two dates.

Enter a date of birth to work out an exact age.

How it works

Age is counted forwards from the date of birth rather than by subtracting numbers and borrowing. Count whole years first, then whole months, then whatever days are left over. Working forwards is what keeps the result correct when a month is shorter than the birth day — subtracting and borrowing 30 days breaks on dates like 31 January.

age = whole years, then whole months, then remaining days
years
Complete years since birth
months
Complete months since the last birthday
days
Days since the last complete month
clamping
A 31st birth day falls on the 28th in February

Worked example

Someone born on 15 January 1990, on 16 September 2026.

  1. 1Count complete years: 1990 to 2026 is 36, and 15 January 2026 has passed
  2. 2Count complete months from 15 January 2026: eight, to 15 September 2026
  3. 3Count the leftover days: 15 to 16 September is 1

36 years, 8 months and 1 day — 13,394 days in total.

Frequently asked questions

How is age counted in India?

By completed years. You are 25 until the day you complete 26 years, which is why forms ask for age as on a particular date. Some competitive exams and government schemes specify an exact cut-off date, so a birthday a day either side of it can change eligibility.

What happens to a 29 February birthday?

In a common year there is no 29 February, so the birthday is treated as 28 February — which is what this calculator does. Some jurisdictions instead treat it as 1 March for legal purposes. It matters rarely, but it is worth knowing that both conventions exist.

Why is age in months not just years times twelve?

It is, for the whole-year part, but the leftover months and days do not divide evenly. Months vary between 28 and 31 days, so there is no fixed number of days in a month to convert by. That is why this calculator reports days separately rather than folding them into a fractional month.

Does this account for time zones?

It works in your device's local calendar date, ignoring the time of day. For a birth in a different time zone the calendar date is what matters, and that is what a passport or certificate records, so the result matches official documents.

Can I use this to find the gap between two dates?

Yes. Put the earlier date in as the date of birth and the later one as the date to calculate on, and the result is the exact gap in years, months and days, along with the totals in weeks and days. Nothing about the calculation is specific to birthdays.

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