Functions Using formulas and functions we can perform calculations based on our cells or we can convert the data in the spreadsheets to a particular format or value so it can be used by another formula or function. The built-in f unctions in Excel can be used to pe rform more complex calculations based on our data. To insert a function we need to select the cell which will hold the function, go to the “Formulas” ribbon and click on the “Insert Function” button. Functions are grouped into categories based on the operations they can be used for.