This will sum every seventh value in column A
=SUMPRODUCT(--(MOD(ROW(A1:A100),7)=1),A1:A100)
best wishes
--
Bernard Liengme
Microsoft Excel MVP
http://people.stfx.ca/bliengme
"Jubilado" wrote in message
...
Hello I am trying to find out how to get a sum of cells with a specific
fixed
interval between them