Hi,
Ig I understand correctly, in third column you could put:

=IF(Sum(a2:b2)=0, " ", sum(a2:b2))

" wrote:

Thanks Toppers.

I have copied the formula to other cells in the column. The only
problem is that when there is nothing in the first two columns, I get
0.00. in the third column.
Is it possible that these cells remain blank untill I enter dates/times
in the first two columns?

Thanks