=number*(1+percent)

If you need to increase a number by a certain percentage, you can use a simple formula that multiplies the number times the percent + 1.

In the example, the active cell contains this formula:

=C6*(1+D6)

In this case, Excel first calculates the result of 1 + the value in D6 (.2) to get 1.2 which it then multiplies times the value in C6 (90) to get a final result of 84:

=90 * (1 + .35)

=90 * (1.35)

=121.5

*Note that must add 1 to the percent if you want to increase a number. If you don't, you'll simply get the amount of the number that the percentage represents.*