Calculate exact age from a date of birth, optionally as of any other day. See years, months, and days plus total days, weeks, hours, the weekday you were born, and a next-birthday countdown, including leap-year edge cases.
Age is computed on whole calendar dates (no time of day) in your local timezone.
We subtract the birth date from the as-of date and normalize negative day or month borrows, so February 29 births roll to March 1 in non-leap years for the next anniversary.
Total days use the exact day count between the two dates; weeks and hours are derived from that total.
age = normalize(asOf − birth) → years + months + days; nextBirthday = next anniversary ≥ asOf
Born on 15 January 2000, as of 20 March 2024.
Years: 2024 − 2000 = 24. Months: March − January = 2. Days: 20 − 15 = 5.
The calculator shows 24 years, 2 months, and 5 days, with total days and a countdown to the next 15 January.
Yes. February 29 birthdays use March 1 as the anniversary in non-leap years, and day counts include 29 February when it exists.
Yes. Change the as-of date. The birth date must not be after the as-of date.
No. The calculation runs entirely in your browser. Nothing is sent to our servers.
Sites disagree on whether to count the end day, how to roll leap birthdays, and timezone cutoffs. We use local calendar dates and clear borrow rules.
It is the number of whole days from the as-of date until the next anniversary of your birth date (0 if today is that anniversary).
This tool provides calendar estimates only and is not legal or medical advice.
Pick a date from the calendar.
Defaults to today. Change it to compute age on another day.
Your age
You were born on a Thursday.
| Total days | 11,440 |
|---|---|
| Total weeks | 1,634 weeks + 2 days |
| Total hours | 274,560 |
| Next birthday | June 15, 2027 (248 days) |