Enter your date of birth to get your exact age in years, months, days, weeks, hours and seconds. Leap-year accurate, using ISO 8601 interval arithmetic.
Frequently Asked Questions
How accurate is this age calculator?
It uses ISO 8601:2019 interval arithmetic, the same standard used in clinical software, government systems and actuarial calculations. Results are exact to the day, with full leap-year correction.
How do you calculate age from a date of birth?
Age in complete years equals the current year minus the birth year, minus 1 if the birthday has not yet occurred this year. Months and days are the remainder, using each month's real length rather than an average.
How does the calculator handle February 29 birthdays?
For people born on February 29, the calculator treats February 28 as the legal age-increment date in non-leap years and February 29 in leap years, preventing annual drift.