I have the following formula in an excel sheet called "Monday", in cell B11:- =IF(ISBLANK(B15),B10,(Staff!$D3-Monday!B15)/Staff!$D3) Where Staff D3= 6.6 (this is hours worked btw) If value entered in B15 6.6 the formula works great.But if value = 6.6 then I get a #DIV?# error because (6/6-6.6/6.6)=0. I want it to just show "N/A" when this is the case. I have checked microsoft help & it says to add an IF(ISERROR argument at the beginning but this doesn't seem to work either as the IF(ISERROR argument is cell B11 & thats the one my formula is in ??? Confused. Hope someone out there can decipher what I'm on about.