PS.....

I wrote:
leapyleigh wrote:
I need to be able to add up the total of every 4th row only.

Do we have the same understanding of what "every 4th row" means? To
me, it means A1, A5, A9, etc for example. The following array formula
will do that (every 4th row starting A1 and ending with the 4th row at
or before A17):

=SUM( IF(MOD(ROW(A1:A17)-ROW(A1),4)=0, A1:A17) )

Type ctrl-shift-Enter, not Enter, after typing or editing the formula.

I should note that that array formula works regardless of where the
range begins. For example, if you wanted every 4th row starting in A2,
simply replace all occurrences of A1 with A2.

Also, when I wrote "ending with the 4th row at or before A17", I meant:
counting from the first row of the range, not from the end of the
range.