Age Calculator
Put in a date of birth and we will tell you exactly how old that is today, or on any other date you choose.
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The formula
Age = the calendar gap between the birth date and the chosen date, counted in whole years, then leftover months, then leftover days.
How the age is worked out
We count whole years first, then the months left over, then the days left over. Someone born on 15 May 1990 is, on 3 October 2026, 36 years, 4 months and 18 days old.
Months are not all the same length, so when the day of the month in the end date is smaller than the birth day, we borrow the length of the previous month. That is the same method a person would use counting on a calendar, and it avoids the odd results you get from dividing days by 30.
What you also get
- Total months, weeks, days and hours you have been alive
- The weekday you were born on
- Your next birthday and how many days away it is
The date box defaults to today, but you can type any other date. That is handy for working out how old someone was when something happened, or how old a child will be when school starts.
Leap years and 29 February
Leap days are counted properly, because we work from real calendar dates rather than a rough 365-day year. If you were born on 29 February, the calculator treats your birthday in a non-leap year as 28 February.
When exact age matters
School admission cut-offs, retirement and pension dates, insurance quotes, age-restricted purchases and sports categories all depend on exact age on a specific date, not just the year you were born. Always check the date a rule applies to.
Examples to check
Type these into the calculator above to see how it behaves. Every result below was produced by the same calculator code that runs on this page.
| What you enter | What you get |
|---|---|
| Date of birth: 1990-05-15; Age at the date of: 2026-10-03 | Age: 36 years, 4 months, 18 days |
| Date of birth: 2000-02-29; Age at the date of: 2026-03-01 | Age: 26 years, 0 months, 0 days |
| Date of birth: 2015-09-01; Age at the date of: 2026-10-03 | Age: 11 years, 1 month, 2 days |
Age Calculator: frequently asked questions
How do I calculate age from a date of birth by hand?
Subtract the birth year from the current year. If your birthday has not happened yet this year, subtract one more. For months and days, count forward from your last birthday.
Can I find out how old someone will be on a future date?
Yes. Change the second date to the future date and you will see their age on that day.
Does it account for time zones?
It uses calendar dates only, so the time of day and your time zone do not change the answer.
Does it take leap years into account?
Yes. Calculations use real calendar dates, including leap days and the different lengths of months.
Is what I enter in this calculator saved or sent anywhere?
No. The calculation runs in your browser, so what you enter is not sent to our servers. We only count, anonymously, whether a tool ran successfully.
Is this calculator free to use?
Yes. It is free, needs no sign-up and has no usage limit.
Last reviewed: October 3, 2026