Use this Age Calculator to find the calendar difference between a date of birth and a selected calculation date. The result is shown in years, months and days. You can calculate your age today or choose another date to check how old you were—or will be—on that date.
How to use the Age Calculator
- Enter your date of birth.
- Choose the date on which to calculate your age.
- Select Calculate to view the result.
- Use Reset to clear both dates.
How the age calculation works
The calculator compares calendar dates rather than simply dividing the number of elapsed days by 365. It first compares the years, then months, and then days. When the calculation date has fewer days in its month than the birth date, it borrows the number of days from the preceding calendar month.
For example, someone born on 15 June 2000 is 26 years, 4 months and 28 days old on 12 November 2026. The result changes when the selected calculation date changes.
Dates, leap years and accuracy
Calendar months have different lengths, and leap years add an extra day in February. The calculator uses the calendar dates entered in your browser. For a 29 February birth date in a non-leap year, the displayed years, months and days follow the date-difference calculation; legal or official definitions of when an age is reached can vary by jurisdiction and purpose.
Check that the date of birth is not later than the calculation date. The calculator rejects invalid dates and future birth dates relative to the selected calculation date.
Frequently asked questions
Can I calculate my age on a past date?
Yes. Enter the historical date in the calculation-date field.
Can I calculate the age of a person born on 29 February?
Yes. The calculator accepts leap-day dates and compares the selected dates using calendar arithmetic.
Does it calculate age only in years?
No. It reports completed years, remaining months and remaining days.
Privacy
The date fields are processed by the calculator in your browser. The dates are not submitted to Tooliday by this tool.