Method
The calculator compares two calendar dates and borrows across month and year boundaries when needed.
How many years, months, and days have passed? Now you know.
Age is calculated using calendar dates. Hours, minutes, and seconds are approximate values based on calendar-day calculations.
Useful context
Use the calculator first, then scan the details below when you want more context about the inputs, result, or assumptions.
The calculator compares two calendar dates and borrows across month and year boundaries when needed.
Enter the date of birth, choose the calculation date, and review the calendar age and alternate time units.
Years, months, and days are calendar values. Total days and smaller units are useful approximations because calendar years vary in length.
For a birth date of August 9, 1996 and a calculation date of August 21, 2026, the result is 30 years and 12 days.
Leap years, February 29, month lengths, and calendar-day totals are handled using UTC-normalized dates.
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