Age calculator
Find an exact age in years, months and days between a birth date and any other date.
Fill in the fields and press Calculate to see your result here.
How this calculation works
The calculator counts whole years, then whole months, then remaining days between the two dates — the same way you’d count age by hand, but accounting correctly for different month lengths and leap years.
Worked example
Born 15 May 2000, measured as of 20 September 2026: that's 26 years, 4 months and 5 days old — or 9,624 days in total.
Tips
Defaults to today
The “As of” field starts on today's date automatically, but you can change it to find the age on any other date, past or future.
Leap-year birthdays
For someone born on 29 February, the calculator counts by calendar date. The legal birthday in non-leap years varies by country.
Check an age on a future date
Change the 'As of' date to see how old someone will be at a wedding, graduation or retirement date.
Total days lived
The days-lived figure is a fun milestone check, for example when you approach 10,000 or 20,000 days.
Frequently asked questions
Can I find the age difference between two people?
Yes — enter one person's birth date as the birth date, and the other's birth date as the “As of” date, if it falls after.
What if 'As of' is before the birth date?
The calculator will show an error, since a negative age isn't meaningful.