ISBLANK with NETWORKDAYS and empty cells

[gibbsmachine]

I've attached a sample of what my problem is. I'm trying to keep track of critical ship dates using NETWORKDAYS. My formula works good until the 2 cells it's watching have no dates in them. This should be an easy fix but I can't figure it out. The formula reads =IF(ISBLANK(E3),NETWORKDAYS($A$2,F3,$A$17:$A$29),NETWORKDAYS($A$2,E5,$A$17:$A$29)). The cell range A2:A17 list the holidays for the year. Cell E3 is a ship date to teflon and F3 is a ship date of the completed job to the customer. Thanks in advance.

[daddylonglegs]

Try this formula in D3 copied down

=IF(COUNT(E3:F3),NETWORKDAYS($A$2,IF(E3="",F3,E3),$A$17:$A$29),"")

[gibbsmachine]

That worked, Thanks.