Conditional formatting on a calculation in excel

Question

I have a performance tracker with three rows, such E3 for the budget, E4 for the actuals, and E5 for the variation. I want the variance to be calculated automatically, but only after I enter the actual value. The budget amount is currently entered into the variance cell when I run the computation because the real cell is currently blank.

Applying the algorithm to the chart with the budgets in place is what I want to do, but I don't want to see a number in the variance field until I enter the actual.

Answer 1

In E5, you could use

=IF(COUNTBLANK(E3:E4)=0,E3-E4,"") 

which would provide a blank result if either of the two above values is missing. However, if E3 or E4 are formulas that may result in an empty value, then I'd evaluate the result of each cell to determine if either were blank: 

=IF(AND(E3<>"",E4<>""),E3-E4,"").