How to add a percentage in Excel?

In Microsoft Excel, you can use a formula to add a percentage to a number. For example, if you want to add 20% to a number, you can use a formula as follows:

In the above example, we have entered formula to calculate a return of 20% of the initial number from cell B2 and then added it to the initial number to obtain an end value in cell C2.
=B2+(20%*B2)

If you want to calculate just the percentage of a number without adding it to the initial number, you can simply change the formula as follows:
=20%*B2

To copy the same formula down the column, click cell C2, move the mouse cursor over the small square green box at the lower-right corner of the selected cell, click and drag it down the column.

If you need to decrease the number by 20%, simply replace the + sign in the formula in cell C2 to a minus - sign. Then click and drag it down to copy the updated formula to cells down the column.