Say your data are in range E1:E13, then
=SUMPRODUCT(--(MOD(ROW(E1:E13),3)=0),E1:E13)

Regards,
Stefi

€žFrank Lennon€� ezt Ã*rta:

I need to count values in alternate cells in MS Excel e.g. adding values in
every 3rd cell. Is there an easy way of doing this?

Thanks in advance

Frank Lennon