Age Calculator

How to use it

This calculator turns a single date of birth into your exact age in years, months, and days, along with several useful totals: total months, weeks, days, and hours you've been alive. It also shows the day of the week you were born on and counts down the days remaining until your next birthday. You can also set an 'age at' date to see how old someone was, or will be, on any other day. Everything is calculated in your browser. Exact age is found by calendar subtraction, not by dividing total days lived by 30. The calculator counts the whole years between your birth date and the target date, then the whole months left over after those years, then the remaining days. This is why the 'months' figure looks uneven from one calculation to the next: real months run 28 to 31 days, so a fixed 30-day divisor drifts by a day or two depending on which months fall in the gap. Leap years are handled the same way — February 29 is treated as a real calendar day when counting years and days, so ages calculated across a leap year stay accurate instead of being off by one. For example, someone born on March 15, 1990, calculated as of July 4, 2026, is 36 years, 3 months, and 19 days old: 36 full years takes you to March 15, 2026; 3 more full months takes you to June 15, 2026; and the remaining 19 days takes you to July 4, 2026. The same date of birth also gives total days, weeks, and hours lived, and the weekday — a Thursday — the person was born on. People use this for more than curiosity. Age is required on forms and eligibility checks (school enrollment, retirement, insurance, age-restricted purchases), for planning milestone birthdays and anniversaries, for tracking the age of a pet or the age of a long-running project (from its start date), and for working out how old a historical figure was on a specific date — how old someone was at a coronation, a treaty signing, or the day a photograph was taken.

Frequently asked questions

How is my exact age calculated?

By calendar subtraction: we count the whole years from your birth date, then the whole months left after that, then the remaining days — the same way you'd say it in conversation (e.g. 34 years, 2 months, 5 days). This is more accurate than estimating from total days divided by 30, since months vary from 28 to 31 days.

Can I calculate my age on a future or past date?

Yes. Set the 'age at' date to any day in the past or future, and the calculator recalculates your exact age (or the age you'll be) as of that date — useful for checking eligibility on a specific deadline or working out how old you'll be for a future event.

Is my date of birth stored?

No. All calculations happen locally in your browser using JavaScript — your date of birth is never sent to a server, logged, or stored anywhere, and it disappears the moment you close or refresh the page. Nothing is saved or shared with third parties.

Why do the months and days in my result look uneven?

Because calendar months aren't equal length. The calculator counts whole months from your birth date, then whatever days are left over — so the day count ranges from 0 to 30 depending on which two months it spans, not a fixed number. This calendar-based method is more accurate than estimating age from total days divided by 30.