Try this:

=IF(OR(I15=0,H15=0,L15=0),"n/a",IF(L15<"",(I15-L15)/L15,(I15-H15)/
H15))

No need for the SUM part.

Hope this helps.

Pete

On Apr 25, 12:59*pm, carol wrote:
Hi.

I've got a basic percentage formula that i would like to enhance.

Currently the formula reads: =sum(I15-H15)/H15

But, i would like it to look into column L (within a specific cell range)
and generate a different formula if it finds a figure in this column.

The new formula would read: =sum(I15-L15)/L15

Any ideas whether to use VLOOKUP or IF??

In addition, I would like the formula to generate a 'n/a' if *an '£0.00' was
found in in the initial cells used. (This only applies to the first part of
the formula). So in the example below,

=sum(I15-H15)/H15

the formula would generate n/a if there was £0.00 in either cel I15 or H15.

Much appreciated.

Carol