How to Calculate Your Exact Age

What does exact age mean?

Your age in whole years is easy to state, but an exact age can also include the number of completed months and days since your last birthday.

For example, someone may be 32 years, 4 months and 11 days old rather than simply 32.

Want to try the idea yourself? Use the Age Calculator.

Why age is not just days divided by 365

Calendar years have different lengths because of leap years, and months range from 28 to 31 days. Dividing a total number of days by 365 therefore does not give a reliable calendar age.

A proper age calculation compares the birth date with the target date using real calendar boundaries.

If you want to explore this topic further, see How to Calculate the Difference Between Two Dates.

How the calculation works

Start with the difference between the two years, then check whether the birthday has occurred in the target year. Months and days are then calculated from the most recent completed calendar boundaries.

If the target day is earlier in the month than the birth day, the calculation needs to borrow days from the previous month, which is why manual calculations can become awkward.

Leap-day birthdays

People born on 29 February still become one year older each year, but the way a particular legal or administrative system treats the birthday date in non-leap years can vary.

For a general elapsed-time calculation, the important point is to use actual calendar dates rather than assuming every year contains the same number of days.

Calculate an age instantly

The Age Calculator compares the dates for you and can show age in years, months and days without manual calendar counting.

It is useful for birthdays, forms, records and any situation where a more precise age than whole years is helpful.