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Calculate age in years, months, and days from a date of birth to today or any date, using real calendar arithmetic.
Whole years and months first, then days: 2000-05-20 on 2025-05-19 is 24 years, 11 months, 29 days.
Dates are calendar dates, so the result is never off by a day because of a UTC offset.
A 29 February birthday is counted as a year older on 28 February in non-leap years, and the convention is stated.
See total months, weeks, and days alongside the years, months, and days.
When you use Age Calculator, your data never leaves your browser. All transformations execute in-memory on your local machine with zero server uploads. Web assets are downloaded to run the tool, but your input data is never transmitted.
No. The calculation runs in your browser. The page does download the code needed to run the tool.
Because months and years have different lengths. Calendar arithmetic counts whole months from the birth date, then the leftover days, which is how ages are normally stated.
In years that are not leap years the birthday is counted on 28 February, so someone born on 2000-02-29 is exactly 1 year old on 2001-02-28.
No. It starts as today in your time zone and stays as it is until you change it. "Use today" resets it.
Calendar age: whole years and months from the date of birth, then the remaining days. The "as of" date starts as today in your time zone and does not change by itself. Someone born on 29 February is counted as a year older on 28 February in years that are not leap years. Dates are read as calendar dates, so time zones cannot shift them. Processed locally in your browser.