Thanks Andy!

I've added a little. It now reads:

=IF(AND(ISNUMBER(F28),ISNUMBER(G28)),(G28-F28)*24-IF((G28-F28)*24>4,0.5,0),Sheet1!C14)

I had a bit of value error trouble with trying to put 5H in sheet1 (meaning five hours holiday).

What I've done to make things easier, is made sheet1 count whole or half day holidays.

So, if it is a full holiday, the value is 1, if half, the value is 0.5.

Now what I do is state in the totaling formula for Trading Hours that if a cell has a value of less than five, ignore it (holidays excluded).

OK, OK. So I still have to check contract holiday hours, manually enter them, but I'm getting there.

Thanks for your help Andy.

If you have any further ideas.

S.