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Age Calculator

Enter a date of birth to get an exact age as of today or any other date — in years, months and days, and as totals in months, weeks and days.

Result

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How to use this calculator

  1. Enter the date of birth.
  2. Leave 'Age as of' on today, or pick another date — for example a deadline or an event.
  3. Read the exact age, the totals and the days until the next birthday.

The formula

Whole months = the most months you can add to the birth date without passing the 'as of' date Years = whole months ÷ 12 (remainder = months) Days = days from that point to the 'as of' date

When a month is shorter than the birth day, the date moves to the last day of that month (one month after January 31, 2026 is February 28, 2026). Leap years follow the Gregorian rule: every year divisible by 4, except century years not divisible by 400.

Worked example

Born August 15, 1990, age on November 6, 2026

  1. From August 15, 1990 to August 15, 2026 is 36 years.
  2. From August 15, 2026 to October 15, 2026 is 2 months (November 15, 2026 would pass November 6, 2026).
  3. From October 15, 2026 to November 6, 2026 is 22 days (16 days left in October + 6).
  4. In total that is 13,232 days.

Exact age: 36 years, 2 months, 22 days.

Frequently asked questions

How is age calculated?

Count the full years since birth, then the full months since the last birthday, then the remaining days. That is how ages are normally stated.

What if someone was born on February 29?

In common years this calculator treats February 28 as the birthday for the countdown. Laws differ on whether the legal birthday is February 28 or March 1, so check local rules for legal purposes.

Does it count leap days?

Yes. Total days are counted from the actual calendar, including every February 29 in the period.

Can I calculate age on a future date?

Yes. Set 'Age as of' to any date on or after the date of birth.

Why do some sites show a different number of months or days?

Month lengths vary, so methods differ at month ends. This calculator steps forward whole calendar months from the birth date and counts the remaining days.

Sources

Last reviewed November 6, 2026. Calculations run in your browser; nothing you type is sent to us. Spotted a mistake? Tell us.