Age Calculator

The age calculator finds an exact age from a date of birth to an age at date. It is useful for birthday countdowns, eligibility cutoffs, school or sports forms, records, and any situation where a rounded age is not specific enough. Results include years with remaining months and days, plus total months, weeks, days, the weekday born, and days until the next birthday.

How to use this calculator

1. Enter the date of birth.
2. Enter the age at date, or leave it set to today.
3. Review the main age result and the supporting totals.

If you need a pure interval between two clock or calendar moments, the time duration calculator may be a better fit. For comparing two people, use the age difference calculator.

How it works

The calculator counts complete calendar years first, then complete calendar months, then leftover days. That avoids the common mistake of subtracting birth years only.

$exact\ age = completed\ years + remaining\ months + remaining\ days$

Worked example

Someone born on June 15, 1990 is 35 years, 0 months, and 28 days old on July 13, 2025. The same result can also be expressed as total days or weeks, which is helpful for forms that ask for age in months or days.

Leap day and cutoff dates

February 29 birthdays can be treated differently by schools, agencies, or jurisdictions in non-leap years. Use the calculator for the calendar math, then check the official rule. Pregnancy and child-development contexts may also use weeks and days, so the gestational age calculator can be more appropriate for prenatal dating.