You could put a formula in E2:
=if(count(c2:d2)<2,"",d2-c2)


Dale G wrote:

A B C D E

Run # Bus # Time Actual Diff

958 0 14:00
850 0 14:08
312 0 14:20
936 0 14:20
970 0 14:33
722 0 14:38

After I make a entry in collum D (actual) I need the difference to enter
automatically in collum E

--

Dave Peterson