How is the age calculated?

The tool calculates the difference between today's date and your birth date, breaking it into complete years, remaining months, and remaining days.

What if my birthday is today?

If today is your birthday, the days and months remainder will be 0, and the years will increment by 1. Happy birthday!

Can I calculate someone's age from a past or future date?

The age calculator always uses today's date as the reference. For a different reference date, use the 'Days between dates' calculator.

How is a 29 February birth date handled?

In years without 29 February, the age goes up on 28 February, the last day of the month. The same rule sets the monthly anniversary for birth dates on the 29th, 30th or 31st in shorter months.

Date of birth calculator

Enter a date of birth to get the exact age as of today in years, months, and days, plus the total number of days lived. For the next birthday date, a birthday countdown, and the weekday you were born, use the full age calculator on this site.

Date of birth

Today:

0 years old

Months remainder

Days remainder

Total days lived

Today:

How it works

All date arithmetic uses the browser's native Date object. Day differences are computed by subtracting timestamps and dividing by 86,400,000 ms. Age counts complete calendar months, shown as years and months, then the days since the last monthly anniversary. The page does not call any external library or server during the calculation. Dates are read at local noon in your browser's time zone, so a daylight saving change from the IANA rules built into the browser never moves a count to the wrong day.

Processing runs in your browser

All calculations happen instantly in your browser tab. Our servers are not involved at any point.

Related operations

For working out an exact age in years, months, and days, try the age calculator. To convert any timestamp into a date, use Unix timestamp. For scheduling work across time zones, see the timezone converter.

Frequently asked questions

How is the age calculated?: The tool calculates the difference between today's date and your birth date, breaking it into complete years, remaining months, and remaining days.
What if my birthday is today?: If today is your birthday, the days and months remainder will be 0, and the years will increment by 1. Happy birthday!
Can I calculate someone's age from a past or future date?: The age calculator always uses today's date as the reference. For a different reference date, use the 'Days between dates' calculator.
How is a 29 February birth date handled?: In years without 29 February, the age goes up on 28 February, the last day of the month. The same rule sets the monthly anniversary for birth dates on the 29th, 30th or 31st in shorter months.

Last reviewed September 30, 2026

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