Fortunately, Excel offers a built-in function, DATEDIF, which makes it easy to calculate elapsed calendar time. I sent Zee a sample solution, and she wrote back that it was exactly what she had in ...

DATEDIF (), which means Date + Dif, is a compatibility function left over from Lotus 1-2-3 that Microsoft adopted in Excel version 2000. It's fallen off current Excel menus, but you can still use it.

To calculate the age, the DATEDIF function, set to check year, determines the number of years between the date in the DOB cell and the current date.

To calculate age in Google Sheets, use the DATEDIF or YEARFRAC formulas. I’ll cover each in detail below. Follow along for screenshots and full formula explanations.