Age Calculator

How the age calculator works

The age calculator takes your date of birth and today's date, then computes the exact duration between them. It breaks the result down into years, months, and days — not just a rounded number. This means if you were born on March 15, 1990, and today is July 12, 2026, the calculator tells you that you are 36 years, 3 months, and 27 days old — not just "36."

Why the exact breakdown matters

For most everyday purposes, knowing your age in years is sufficient. But there are situations where the exact breakdown in months and days is important. Infant developmental milestones are tracked by months (not years) — a 14-month-old is at a very different developmental stage than a 23-month-old, even though both are "1 year old." Legal age thresholds (18, 21, 65) are determined by the exact date, not the calendar year. Insurance and pension calculations often require precise age in days.

How leap years are handled

The calculator automatically accounts for leap years. If you were born on February 29 (a leap day), the calculator handles this correctly — in non-leap years, your birthday is typically celebrated on February 28 or March 1, but the exact age calculation uses the actual calendar dates. The underlying date library (date-fns) handles all edge cases including month-length variations and leap year rules.

Privacy: your birth date stays in your browser

Your birth date is never sent to our servers. The entire calculation happens in your browser using JavaScript. When you use the "Share" feature, a URL is generated with your birth date as a parameter — but this URL is only shared when you choose to copy it. We don't track or store any birth dates.

Related tools

• Date Duration Calculator — find the time between any two dates.
• Add/Subtract Dates — find a future or past date.
• Calendar Generator — create and print a yearly calendar.
• Week Number Calculator — find the ISO week number.