Age Calculator
Find calendar age on a target date.
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Formula / Calculation Method
Subtract complete calendar years, then complete months, then remaining days.
Example Calculation
2000-01-01 to 2025-01-01 is 25 years and 9,132 days.
Understanding the Result
End-of-month anniversaries clamp to the last valid day. February 29 anniversaries use February 28 in non-leap years. Dates have no time zone.
What is the Age Calculator?
Find calendar age on a target date.
How to Use
Enter the birth date and the date on which to measure age. The target defaults to the current local calendar date.
Select Calculate after entering your values. Text tools update as you type. Reset restores the starting fields.
Interpreting the Calculation
Years, months and days describe a calendar interval. Complete months and elapsed days are separate measures; they are not obtained by multiplying years by 365.
Common Questions
What happens with a February 29 birthday?
This tool uses February 28 for anniversaries in non-leap years. Legal and institutional birthday conventions can differ.
What assumptions does this tool use?
End-of-month anniversaries clamp to the last valid day. February 29 anniversaries use February 28 in non-leap years. Dates have no time zone.
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