Method
How the age calculator works
Completed years are counted first, then complete calendar months, followed by remaining days. Future birth dates are rejected as invalid age ranges.
Counting clock time within a day rather than calendar days? The hours calculator measures the hours and minutes between two times, the time card calculator totals a week of shifts, the add time calculator adds or subtracts durations, and the military time converter switches between 24-hour and AM/PM times. The rest are in the time calculators collection.
Example
Age calculator example
A birthday must have occurred in the reference year before another completed year is counted.
FAQ
Age calculator FAQ
Is the reference date included?
Age is measured at the start of the reference date using calendar components.
How are leap-day birthdays handled?
Calendar arithmetic uses valid month-end dates when a year has no 29 February.
Is age information stored?
No. Both dates remain in this page and are not saved by default.