Free Online Age Calculator

1. Pick the birth date in the first date field.
2. Optionally change the target date — it defaults to today.
3. Read the breakdown: years, months, days appear at the top.
4. Check the equivalent weeks, hours, and seconds below for context.

"How old am I in days?" is harder than it looks. Month lengths vary from 28 to 31, leap years add an extra February 29, and rolling backwards through month boundaries needs explicit borrow logic. Naive subtraction (today minus birthday divided by 365.25) is good to within a day or two but routinely wrong on edge cases.

This tool subtracts the two dates with proper calendar arithmetic. It reports the exact years-months-days breakdown plus equivalents in weeks, total days, hours, minutes, and seconds — the last few are mostly for entertainment value.

The target date defaults to today and can be set to any past or future date, useful for figuring out how old someone will be on a wedding day, or how long ago a historical event was.