Try adding some error handling to the start of your formula eg =IF(H18<>"", (O18-H18)/ABS(H18), "") Which in Lehmanns terms means if H18 is not blank then return the value and if it is then remain blank
Can you show me the spreadsheet?
Also is the ABS function required?? Is it possible for the number to be less than 0?? If the answer is no then the ABS function is not required.
If it can be negative then try this =IF(H10>0, (O10-H10)/H10), "")
Otherwise copy and paste this formula =IF(H10<>"", O10-H10/(H10), "")