Age Calculator
Your exact age — in years, months and days — plus your next birthday and the day of the week you were born.
| Total days lived | |
| Total weeks | |
| Total hours | |
| Born on a | |
| Next birthday |
What is this tool?
Knowing your age in years is easy; knowing it exactly is surprisingly useful. Schools, sports leagues, insurance applications, retirement accounts and government forms in the US often care about your precise age on a specific date — the first day of school, the enrollment deadline, or the day you turn 59½ or 62 for retirement benefits. This age calculator does the calendar math correctly, including leap years.
Enter your date of birth in the US MM/DD/YYYY format and, if you need your age on a particular day, set the 'age as of' date too. You will get years, months and days, the total number of days and weeks you have lived, the weekday of your birth, and how many days remain until your next birthday.
How to use it
- Enter your date of birth using the date picker (MM/DD/YYYY).
- Optionally set an 'age as of' date — leave it as today for your current age.
- Click Calculate to see the full breakdown.
Formula & method
Worked example
Someone born on 03/15/1990 is 35 years old in March 2025 — precisely 35 years, 0 months and a few days on their birthday. By that day they have lived about 12,784 days, or roughly 1,826 weeks.
Frequently asked questions
Why does the age on a form sometimes differ by a day?
Some systems count age simply by subtracting years, which can be off by one around your birthday. Exact date-based calculation, used here, accounts for whether this year's birthday has already happened.
What day of the week was I born?
The calculator shows it in the results — for example, July 4, 1976 fell on a Sunday. It is a fun detail for birth announcements and family history projects.
Can I calculate the age of a child for school enrollment?
Yes. Set the 'age as of' date to the school district's cutoff date (often September 1) and enter the child's date of birth to see the exact age on that day.