Age Calculator
Calculate age in years, months, and days from a date of birth, plus total months, weeks, and days lived. Free and runs in your browser.
Independently verified for accuracy
Calculator by Toolsloft ↗- Age
- 36 years, 0 months, 23 days
- Total months
- 432
- Total weeks
- 1,881
- Total days
- 13,172
- Born on a
- Friday
Find out exactly how old someone is from a birth date. Enter the date of birth and the tool shows the age in years, months, and days, along with the total months, weeks, and days lived and the weekday you were born on. The reference date defaults to today but you can set any date to check an age in the past or future.
How this is calculated
The age in years, months, and days follows the relativedelta convention: the whole-month gap is added back to the birth date (clamping to the length of a shorter month), stepped back a month if it overshoots, and the remaining days are counted. Totals are exact whole-day counts using UTC calendar days, so leap years are handled automatically.
How to use
- Enter the date of birth in the first field.
- Leave the second field on today, or set a different reference date.
- Read the age breakdown and the running totals below.
Examples
- Age today:
Born 1990-06-15, as of 2026-07-08 → 36 years, 0 months, 23 days - Leap birthday:
Born 2000-02-29, as of 2026-02-28 → 26 years
FAQ
- How is the age worked out when the day does not line up?
- When the reference day is earlier in the month than the birth day, the tool counts back one whole month and adds the leftover days, the same way age is stated in everyday use. Shorter months are handled by clamping to the last day of the month.
- What happens with a February 29 birthday?
- In years without a February 29, the anniversary is treated as February 28, so a leap-day birthday still turns a full year on the 28th in common years.
- Is my date of birth sent anywhere?
- No. The calculation runs entirely in your browser and nothing you type is uploaded.