Let me break that formula down and see what it's doing. Let's say h is the number of hours worked and r the hourly rate; in that case your formula saysExcel doesn't know what you want to do, only what you tell, of course; and it it won't accept this formula because you need also tell it what value to use if the condition is false. But forget about fixing that part of it; it seems to me that you need to start over. You want D8 to be something like this:Or even simpler:"The part of h > 40" could be written as just h-40, but if h < 40 that yields a negative number. You want MAX(h-40,0); that picks the larger of the two numbers, h-40 and 0, so that if h > 40 then you get h-40 but otherwise you get 0. So in D8 you put