Excel – Age Calculation – How to Get Age from Date of Birth (DOB)

The easiest way to calculate person’s age from using their birthday in Excel is by utilizing undocumented DATEDIF function. DATEDIF is a built-in Excel function, however, unlike all the other built-in functions it will not auto-populate, show up in auto-complete or give tooltips on the function.

So how do you use DATEDIF function?

The syntax for the function is as follows:

DATEDIF([start-date],[end-date],[return type])

To calculate person’s age using datedif function you can use the following formula:

Assumptions:

• A1  –  the cell where you have person’s birthrate

Enter the formula where you want to output the age:

=DATEDIF(A1,TODAY(),”Y”)

If you do not want to use the dynamic TODAY() function you may reference to a call with a date on which you would like to calculate the age.

Assumptions:

• A1  –  the cell where you have person’s birthrate
• B1 – the date when you want to calculate teh age

Enter the formula where you want to output the age:

=DATEDIF(A1,B1,”Y”)