Time & Date
Age calculator
Enter your date of birth and a reference date (today by default) to compute your exact age in years, months, and days, plus totals in weeks, days, and hours.
Age
36 y 4 m 24 d
Total months
436
Total weeks
1 899
Total days
13 293
Total hours
319 032
Formula
Age looks simple but has subtle edge cases around month boundaries. This calculator handles them by counting whole years first, then months, then borrowing days from the previous month if the day-of-month rolled over. The result matches how a passport office, school registrar, or doctor would compute age — never off by a day.
The browser computes this in local time, so for births near midnight there can be ±1 day variation depending on your timezone. For legal or actuarial purposes, use UTC and the actual time of birth.
Examples
- 01Born 1990-05-15, age on 2024-03-10→ 33 years, 9 months, 23 days
- 02Born 2000-02-29 (leap day), age on 2024-02-28→ 23 years, 11 months, 30 days (turns 24 the next day)
- 03Born today, age on today→ 0 years, 0 months, 0 days · 0 total days
FAQ
- JavaScript's Date object handles leap years natively. February 29 birthdays read as 'still 23' until February 28 in a non-leap year, then tick over to 24 on March 1. This matches the most common legal convention.