Menu

Age Calculator

Work out an exact age in years, months and days from a date of birth, on any date you choose.

Runs in your browser — dates never leave your device

Leave as today, or pick another date.

How to use the Age Calculator tool

  1. Enter the date of birth in "Date of birth".
  2. Leave "Age at this date" as today, or pick another date, such as a form's deadline.
  3. Read the result, which updates as you type, or press "Calculate".
  4. Press "Copy result" to paste the answer into a form or message, or share the page link, which keeps your dates.

Find an exact age in seconds

Knowing someone’s age in whole years is easy. Knowing it exactly, in years, months and days, takes more care: months have different lengths, leap years add a day, and birthdays on the last day of a month need special handling. This age calculator does that counting for you and shows how it got the answer.

What the calculator shows

  • Age in years, months and days, such as 24 years, 3 months, 12 days.
  • Totals: age expressed as total months, total weeks (with remaining days), total days and total hours.
  • Day of the week you were born, for example Tuesday.
  • Your next birthday: the date, the day of the week, and a countdown in days, plus the age you will turn.

Results appear as soon as both dates are filled in. Press “Copy result” to paste a summary into a form or a message.

The formula behind the result

The calculator uses calendar arithmetic rather than dividing days by 365:

  1. Count the whole months from the date of birth to the target date. A month is complete when the same day number is reached in a later month.
  2. Divide those months by 12: the quotient is the years, the remainder is the months.
  3. Count the days left between the last completed month and the target date.

For example, from 15 May 1990 to 22 September 2024 there are 412 complete months (34 years and 4 months), plus 7 days from 15 September to 22 September. So the age is 34 years, 4 months and 7 days.

When a birth date falls on a day that a later month does not have, such as the 31st, the month is treated as complete on that month’s last day. The same rule means that a 29 February birthday is counted as 28 February in years that are not leap years.

When an exact age matters

  • School and university admissions often set a minimum or maximum age on a cut-off date.
  • Job and exam applications ask for age on the closing date of the advertisement.
  • Sports and competitions group people by age on a set day.
  • Retirement, pensions and insurance calculations often depend on age at a specific date.
  • Personal milestones, such as counting down to a birthday or celebrating 10,000 days old.

For any of these, set “Age at this date” to the date stated in the rules, not today. Always follow the official instructions if they define age differently.

Checking an age limit

Application rules are often written as “at least 18 years old on 1 January” or “under 30 on the closing date”. To check one:

  1. Enter your date of birth.
  2. Set “Age at this date” to the date named in the rules.
  3. Compare the years, months and days with the limit. If the rules say “under 30”, someone aged exactly 30 years and 0 days does not qualify.

Sharing a result

The page keeps your dates in its address, so you can bookmark the result or send the link to someone else, and they will see the same calculation. If you prefer not to share your date of birth, use “Copy result” instead and send only the answer.

Privacy

The calculation runs entirely in your browser. Your date of birth is not sent to a server or saved anywhere by this site.

Works on any device

Use it on a phone, tablet or computer in any up-to-date browser, with no app or account. On most phones, tapping a date field opens the phone’s own date picker.

Other calculators

To turn exam marks into a percentage, use the Percentage Calculator. Students can work out a term average with the GPA Calculator or combine semesters with the CGPA Calculator. For a quick health check for adults, try the BMI Calculator.

Frequently asked questions

How does the age calculator work?

It counts the whole calendar months from the date of birth to the chosen date, splits them into years and months, and then counts the remaining days. It also shows totals in months, weeks, days and hours.

How is age calculated for someone born on 29 February?

In years without 29 February, the birthday is counted as 28 February. For example, someone born on 29 February 2000 turns 25 on 28 February 2025.

Can I find my age on a specific date?

Yes. Change "Age at this date" to any date, past or future. This is useful when a form asks for your age on a cut-off date.

How many days old am I?

The result shows "Total days" between your date of birth and the chosen date, along with total weeks, months and hours.

Is my date of birth stored?

No. The calculation happens in your browser. The dates only appear in the page address if you share the link.

Why are total hours an estimate?

The calculator works with dates, not times of day, so total hours are total days multiplied by 24. Your actual time of birth is not included.