Age calculator

How to calculate your age

1. Enter your date of birth in the date field.
2. Your exact age in years, months, and days appears immediately.
3. Switch between views using the panel: Years & months, Total days, or Birthday countdown.
4. Scroll down to see all details including total hours lived and your next birthday.

Common uses

• Calculating your exact age for a form, application, or official document
• Finding how many days you have lived as a fun personal milestone
• Counting down the days until your next birthday or a friend's birthday, or estimate a pregnancy due date from a known conception date
• Verifying someone's age eligibility (voting, driving, retirement) alongside a tool that counts days between two dates

Technical specification

• Algorithm or formula: Calendar difference using the Gregorian calendar. Whole calendar months are counted first, then the days since the last monthly anniversary. When a month has no such day (29 February in a common year, or the 31st), its last day counts as the anniversary, the same rule the birthday countdown uses. Total days count calendar days, and hours and weekday derive from JavaScript Date arithmetic.
• Browser API or library: Native JavaScript Date arithmetic, with numbers formatted by toLocaleString(). No external library.
• Input limits: Any past date up to today that the date picker accepts. A future date gives no result. Practical use covers any human lifespan.
• Output: Plain text values displayed in the page. Includes years, months, days, total days, total hours, next birthday date, weekday of birth.
• Known limitations: Does not account for time zone changes around the moment of birth. Months are treated as variable-length calendar units, not a fixed 30 days.

Frequently asked questions

How is exact age calculated?

The calculator counts the whole calendar months from your date of birth to today, shown as years and months, then the days since the last monthly anniversary. Leap years and months of different lengths are handled.

Is this age calculator free?

Yes, completely free. No account, no sign-up, and no data is ever sent to our servers.

How are 29 February birthdays handled?

In years without 29 February, the tool treats 28 February as your birthday: your age in years goes up that day and the countdown targets it. In leap years the countdown targets 29 February.

What else does the calculator show?

Along with your age in years, months, and days, the calculator shows your total days lived, your age in hours, your next birthday date, how many days until it arrives, and the day of the week you were born.