Age Calculator

Enter a date of birth to get the exact age in years, months, and days, plus totals in months, weeks, days, and hours. Set a different target date to find someone's age on any day.

Date of birthAge at date

What this tool does

Pick a date of birth and it works out the exact age down to the day: so many years, months, and days. It also gives you the same span counted in total months, weeks, days, and hours, plus a countdown to the next birthday. By default it measures up to today, but you can set any target date to see the age on that specific day.

How the date math works

Ages are counted the way a calendar works, not as a flat number of days divided by 365. The calculator borrows days from the previous month and months from the year when needed, so it handles months of different lengths and leap years correctly. That's why the years-months-days result always lines up with how you'd count it by hand.

When you'd use this

Filling in a form that asks for an exact age, planning a milestone birthday, or figuring out how old someone was on a past date. It's also handy for working out age gaps or checking eligibility cutoffs. The dates you enter stay in your browser and are never sent anywhere.