According to the help file (https://support.office.com/en-us/art...3-db171d0c42a7 ), the second "num_digits" argument is required. What you have typed/pasted into your post does not have a "num_digits" argument =ROUNDUP(ROUND(SUM(I8*F8))*2,0)/2,num_digits). If what you have typed is exactly what you are trying to enter into Excel, then you need to decide how many digits the ROUNDUP() function should round to and enter it in the "num_digits" argument.