Productivity Percentage Formula

This might be what you're after:
Sum percentages (B18:F18)
Divide that total by regular hours worked that are greater than 0:

= SUM($B$18:$F$18)/SUMPRODUCT(--($B$17:$F$17>0))

Ok used to your formula however the #div/0! is still there and as a result it will not total the % row. so for example on that same sheet i put 0 for hours worked and 0 for billable hours and got the above error due to dividing a number by 0. The % row is formula based on dividing row 16 by row 17. I put the formula you gave me in to total column on the % row. if there is a number in there then it works fine. I also tried the #n/a but it still has the same result.