=(Sum(IIf(nz([acppassfail],0)="Passed",1,0)))/(Sum(IIf(nz([ACPCompletionDate],0)>0,1,0)))


How do I get rid of #Div/0! and #Num!?

The abobe code runs fine until the field I am refering to is vacant.

Thanks
Dianna

In your denominator, you wrote your NZ function to return a 0 (zero) if the field value is null, change the null return value to something that won't return an error, possibly the current date.

Also the IIF statement in your denominator is returning a 0 (zero) if the condition is false.

I suggest you rethink the whole expression.