Age Calculator
Find an exact age in years, months and days from a date of birth.
Enter values
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Step by step
The formula
age = (reference date) − (date of birth)
Exact age is harder than subtracting years, because months have different lengths and leap years add a day. This works down the units in order — whole years, then whole months since the last birthday, then leftover days — borrowing from the previous month when the day count goes negative.
All calculations run locally in your browser and update instantly as you type.
Example calculations
Common questions this calculator answers — select one to load its values.
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Frequently asked questions
How is exact age calculated?+
We count full years, then remaining months, then remaining days between the two dates, accounting for varying month lengths and leap years.
All calculations run locally in your browser. Nothing you type is sent to a server.