No need to trace, I assumed rows you are going across, use

=SUMPRODUCT(--(MOD(COLUMN(S14:GV14),3)=0),S14:GV14)


--

Regards,

Peo Sjoblom



"Ken" wrote in message
...
Thank you for the reply. I cut and pasted you suggestion into my sheet and
modified the array range to fit my requirements (S14:GV14). however, the
result was a value# error. I will see if I can trace the error.

ken

"Peo Sjoblom" wrote:

One way

=SUMPRODUCT(--(MOD(ROW(D1:D30),3)=0),D1:D30)

will sum D3,D6, D9 and so on


--

Regards,

Peo Sjoblom


"Ken" wrote in message
...
I have a fairly large spreadsheet. In a particularl section I would
like
to
sum the values contained in every third cell. Currently I have over 30
cells
I would like to sum and the only way I can find to do so is by
referencing
each cell individually with a + sign in front. All of the +cell
references
is
cumbersome and inefficient.