Age & Date Difference Calculator

Calculate your exact age or any date difference

Enter a birth date and an "as of" date to see your age broken down into years, months, and days, plus the total number of days elapsed. The as-of date defaults to today so you can read your current age instantly. All calculation happens locally in your browser — nothing is sent to a server.

The tool handles month-boundary borrowing correctly: if the day component would go negative, it borrows from the previous month using that month's actual day count, so leap years and short months are always accounted for accurately.

FAQ

Why does the "days" field show a large number even for a recent birthday? The "Days" stat shows the leftover days after full months are counted, not the total. "Total days" is the raw day count between the two dates.

Does it handle leap years? Yes. The month-borrow step looks up the real length of the preceding month, so February 29 birthdays and short months are handled correctly.

Can I compare two arbitrary dates? Yes — just set the birth date to the earlier date and the as-of date to the later date.