I need to know the function to enter in order to make my spreadsheet give me

What percent of this (2000) is that (200)

We know the answer is 10% but I want my spread sheet to figure this automatically for any number.

Put your Numerator in A1, your Denominator in A2, and in A3 put =round(A1/A2 ,3)and then format cell A3 as percentage. This will give you an answer to the nearest tenth of a percent. If you want it to the nearest whole percent, change ',3' to ',2'.

TD