How to calculate Night Differential

Originally Posted by mar_t

whenever there is no entries in Start and Stop cells the result is 8, would appreciate if you could set as zero

Given Times are numeric values you can add a pre-emptive COUNT test

=IF(COUNT(C2:D2)<2,0,MAX(0,MIN(D2,INT(C2)+1+"6:00")-MAX(C2,INT(C2)+"22:00")))