Age Calculator

How It Works

The calculator compares your date of birth to the target date using calendar-accurate month and year boundaries, so results correctly account for different month lengths and leap years rather than simply dividing total days by 365.

Formula

Years, months and days are found by subtracting the birth date's year, month and day components from the target date's, borrowing from the next higher unit when a component is negative (for example, borrowing a month's worth of days when the target day of month is earlier than the birth day of month).

Example

Someone born on 29 February 2000 turns 24 on 29 February 2024, a leap year, and the calculator correctly rolls that anniversary to 1 March in non-leap years.

Frequently Asked Questions

Does this calculator account for leap years?

Yes. Ages are computed using real calendar dates, so leap years and variable month lengths are handled automatically rather than assumed to average out.

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

Yes. Use the "Calculate Age On" field to choose any target date, and the calculator will show your age as of that date.

Why does my age in months differ from my age in years times twelve?

The months figure is the remainder after whole years are counted, not a separate independent calculation, so it will always be less than 12.