How to work out age or years of service with DATEDIF

This counts the whole years between a start date and today, for an age from a birthday or length of service from a hire date.

The formula

=DATEDIF(B2,TODAY(),"y") in column C

What each part does

B2
The earlier date.
TODAY()
Today, recalculated every time the sheet opens.
"y"
Answer in whole years.

How it works, and what to watch for

DATEDIF with "y" counts complete years, so someone one day short of a birthday still reads as the younger age, which is what you want.

DATEDIF is an old function that does not appear in the formula tips, but it works in every version of Excel.

For an age at a fixed date rather than today, swap TODAY() for that date.

Questions

Why can I not see DATEDIF in the suggestions?

It is a remaining from an older Excel that Microsoft never added to the tooltip list. It still works perfectly if you type it in full.

How do I get years and months?

Run DATEDIF twice, once with "y" for the years and once with "ym" for the remaining months, and join the two.

The example sheet

Staff Joined Years
Anne 2019-04-01
Lukas 2023-11-20
Sofia 2015-07-09

If this helped, these are close by

More on DATEDIF, and every walkthrough that uses it.

Formula Steps Watch how Excel formulas are built. Download the sheet.

Settings: separator, Excel version

Argument separator

Set by your computer's language, not by the file. A frequent cause of a correct-looking formula being rejected.

Excel version

XLOOKUP, IFS, TEXTBEFORE and TEXTJOIN need Microsoft 365 or 2021; older versions return #NAME? instead. Choosing the older one switches every walkthrough to a formula that works there.