Age Calculator — Free Online Tool

The Age Calculator takes a date of birth and a target date (defaulting to today) and works out the exact difference in years, months, and days — correctly handling the parts that trip up simple date math, like variable month lengths and leap years, so 'years since birth' doesn't drift off by a day here and there the way naive subtraction can.

Beyond current age, entering a future or past date instead of today calculates age as of that specific date — useful for eligibility rules that specify an exact cutoff ('must be under 18 as of enrollment day') or figuring out how old someone was on a particular historical date. The tool also breaks the result down into total days and total weeks lived, which is a common way people mark milestone birthdays beyond the standard years-and-months figure.

Because dates and leap years are handled precisely — not approximated with a flat 365.25-day average — the day count stays accurate across long spans, including multiple leap years, rather than compounding small errors the way rough date-math shortcuts do.

The calculation runs immediately in your browser from the date you enter; no birth date or personal information is transmitted or stored anywhere.

Our Age Calculator is completely free to use with no signup required. For this tool, processing runs in your browser — your files and data stay on your device and are not uploaded to our servers.

Whether you are a developer, designer, student, or business owner, this tool is designed to save you time and make your workflow more efficient. Bookmark this page to access it whenever you need it — it will always be free.