Can I calculate age on a past date?
Yes. Select any date on or after the birth date.
Age Calculator
Calculate your age in years, months and days on a chosen date.
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Adjust the values below to get a clear estimate.
Calendar-based age
Years, months and days are counted from the birth date to the selected date. In a non-leap year, a February 29 birthday is treated as February 28 for the annual birthday comparison.
Elapsed calendar years, then remaining calendar months, then remaining daysWorked example
Age on a specific date
Inputs: birthDate: 2000-01-15 · asOfDate: 2025-06-20
Illustrative result: 25 years, 5 months, 5 days
The result counts calendar boundaries from January 15, 2000 through June 20, 2025.
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Frequently asked questions
How are leap-day birthdays handled?
For the age-year boundary in a non-leap year, February 29 is treated as February 28.