Tips & Tricks 70 – Sum Every Even Row

If your range is A1:A100, use following formula.

=SUMPRODUCT((A1:A100)*(MOD(ROW(A1:A100)-ROW(A1)+1,2)=0))

This is a generic formula, hence if your range is B7:B50, your formula will become

=SUMPRODUCT((B7:B50)*(MOD(ROW(B7:B50)-ROW(B7)+1,2)=0))