Age Calculator

Enter a date of birth to get the exact age in years, months and days on any date, plus the total in days, weeks and hours, the next birthday and the day of the week the person was born. It uses real calendar months, not an average year length.

Free, no signupNo daily limitRuns in your browser - nothing you enter is uploadedUpdated 7 October 2026

Date of birth

Age at

29 February birthdays in common years fall on

-Total months

-Weeks

-Total days

-Hours (days × 24)

-Next birthday

-Day of the week born

How the exact age is counted

Age is counted the way people count it, on the calendar, in three steps:

Whole years up to the most recent birthday on or before the "age at" date.
Whole months from that birthday. A month is complete when the same day of the month comes round again. If a month is too short to have that day - the 31st in a 30-day month - its last day counts instead.
Remaining days, counted on the calendar.

No average year length (365.25 days) or average month (30.44 days) is used anywhere, so the answer always matches counting on a calendar. Totals in days and weeks are exact calendar-day counts; hours are those days × 24.

The 29 February rule

Someone born on 29 February has no birthday in three years out of four. There is no single rule for this: some places treat 28 February as the birthday in those years, others 1 March. This calculator uses 28 February by default and lets you switch. The choice only matters on those two days and for the next-birthday date.

Worked example

Born 15 January 2000, age on 7 October 2026:

last birthday 15 Jan 2026 → 26 years + 8 months 15 Sep 2026 (15 Oct is still ahead) + 22 days 15 Sep → 7 Oct = 26 years, 8 months, 22 days total days 9,762 · born on a Saturday next birthday 15 Jan 2027

Leap-day example: born 29 February 2000. On 28 February 2001 the person is 1 year old under the 28 February rule, and still 0 under the 1 March rule.

What this calculator does not do

Ages are calculated in whole calendar days; the time of birth and time zones are not taken into account.
Total hours ignore daylight saving time changes.
Dates use the Gregorian calendar for every year, including dates before it was adopted.

Frequently asked questions

How is the exact age calculated?

First the whole years are counted up to the last birthday. Then whole months are counted from that birthday, and the remaining days are counted on the calendar. It uses the real length of each month and leap years, not an average of 365.25 days.

How are 29 February birthdays handled?

In years without a 29 February, the birthday is treated as 28 February by default. You can switch it to 1 March. Different countries and organisations use different rules, so the choice is yours.

What if the birth day does not exist in a month, like the 31st?

A month is complete when the same day of the month comes round again. If that month is shorter, its last day counts instead, so 31 January to 29 February 2000 is exactly one month.

Can I find someone's age on a past or future date?

Yes. Change the "Age at" date to any date on or after the date of birth, for example an exam cut-off date or a retirement date.

Are the hours exact?

Total hours are calendar days multiplied by 24. They do not adjust for daylight saving changes or the time of day you were born.

Is the date of birth stored?

No. The calculation runs in your browser, the dates are not sent anywhere, and nothing is saved when you leave the page.

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Step-by-step guide: How to calculate exact age →

Built and checked by Taimur Hassan Siddiqui, who has more than ten years in computer-science education. The formulas on this page are covered by an automated test suite, and the worked example on this page is one of its cases. Last updated 7 October 2026.