Does the age calculator account for leap years?

Yes. It calculates the real calendar difference between two dates, so leap days (February 29) are counted correctly rather than assumed away.

Why does my age in months and days look different from a simple date subtraction?

Because months have different lengths (28 to 31 days), an accurate age calculation has to borrow from the previous month using its real day count whenever today's day-of-month falls before the birth day-of-month, rather than assuming every month is 30 days.

Can I calculate age between any two dates, not just to today?

Yes, the calculator works between any start and end date, which is useful for calculating age at a specific past or future event, not only current age.

Age Calculator

Find your exact age, next birthday countdown, and fun facts about when you were born.

Date of Birth

Calculate age as of

How to use

Enter your date of birth using the date picker.
The "Calculate age as of" field defaults to today — change it to calculate age at any specific date.
Click Calculate Age to see your exact age in years, months, and days.
Scroll down to see your total age in months, weeks, days, hours, minutes, and seconds.
Find out what day of the week you were born and when your next birthday is.
Use Share Result to copy a summary of your age to the clipboard.

About this Age Calculator

Calculating exact age sounds simple until you try to do it by hand. Months have different lengths, leap years add a day every four years, and if today's date hasn't reached the birth day-of-month yet this month, you have to borrow from the previous month — the same way you'd borrow in subtraction.

How the calculation works

The tool takes the difference between two dates and breaks it into years, months, and days rather than just a raw day count. It compares the birth month and day against today's month and day: if today's day-of-month is earlier than the birth day-of-month, it borrows a month (using that month's actual day count, not a flat 30) and adjusts.

Worked example

Someone born March 15, 2000, checking their age on January 10, 2026: from March 2000 to January 2026 is 25 years and 10 months, but today (the 10th) hasn't reached the birth day (the 15th) yet, so one month is borrowed — giving 25 years, 9 months, and 26 days (December has 31 days: 31 − 15 + 10 = 26).

Why leap years complicate things

Anyone born on February 29 only has a "real" birthday once every four years. Most systems treat February 28 or March 1 as the observed birthday in non-leap years for legal and practical purposes, but the exact-age math itself still counts the true calendar days between the two dates, leap days included.