Skip to content
QuickKit

Home › Age Calculator

Age Calculator

Enter a date of birth to see an exact age. You can also change the "age at" date to find out how old someone was, or will be, on a specific day.

Pick a date of birth to see the result.

How exact age is calculated

Age in years is the number of birthdays you have had. To get the months and days as well, this calculator counts whole months forward from the date of birth and then counts the leftover days. If you were born on 15 May 1990, then on 3 October 2026 you are 36 years, 4 months and 18 days old, and you have lived 13,290 days. All dates are handled as plain calendar dates, so time zones and daylight-saving changes cannot shift the answer by a day.

Short months and leap-day birthdays

Month lengths vary, so "one month after the 31st" needs a rule. Here, when the target month is shorter, the day is clamped to the last day of that month: one month after 31 January lands on 28 February (or 29 in a leap year). Leftover days are then counted from that point. A birthday on 29 February is the other awkward case. In non-leap years this calculator treats the birthday as 1 March when it works out the next birthday. Some places and organisations use 28 February instead, and legal rules differ by country, so check the relevant rule if the exact date matters for something official.

Useful ways to use the "age at" date

  • Eligibility checks: find out whether someone will be old enough on a deadline, such as a school-entry cutoff, a race start date or a membership requirement.
  • Looking back: work out how old a person was at a historical event, a wedding or a graduation.
  • Planning ahead: see how old a child will be at the start of the next school year, or how long until a milestone birthday.
  • Records and forms: confirm an age you have to write down in years and months, as paediatric and school forms often ask.

What else you see

Besides the main result, the calculator shows your total lived time in months, weeks and days, and an approximate figure in hours. The hours number is simply days multiplied by 24, because the time of birth is not asked for. You also see the weekday you were born on, and the date and countdown for your next birthday, including the age you will turn. If today is your birthday, the countdown shows that instead of a number of days.

Different age systems

This tool uses the international method, in which a person is zero until their first birthday. Traditional East Asian age-counting methods start from one at birth and add a year at the new year, so the number can be one or two years higher. South Korea moved most legal and administrative uses to the international method in 2023, but traditional counting may still come up in conversation or in older documents. Your date of birth is never sent anywhere. The sum runs in your browser, and nothing is stored once you close the page.

Frequently asked questions

How do I calculate my exact age?

Enter your date of birth in the calculator. It counts the whole years since that date, then the remaining whole months, then the leftover days, and shows the totals in months, weeks and days as well.

Can I find out how old someone was on a past or future date?

Yes. Change the "Age at" date to any date on or after the date of birth, and the result updates to show the age on that day.

How are people born on 29 February handled?

In non-leap years this calculator treats the birthday as 1 March when finding the next birthday. Other places use 28 February, and legal rules differ, so check the local rule if you need an official answer.

Does the calculator store my date of birth?

No. The calculation runs entirely in your browser. Your date of birth is not sent to a server or saved, and it disappears when you close or refresh the page.

Why might my age differ from another calculator?

Calculators use different rules for months of unequal length, and some count time of day. This one counts whole calendar months and ignores the time of birth, which is the most common approach.

More free tools