I have data in column D1 all the way down and need to sum this. I need to sum it every three. The first group is easy, sum(d1:d3) results in E1, sum(d4:d6) results in E2, I need this to happen all the way down. I know it can be done because I've done it before but have forgotten how to, can anyone help?

On column F, input a series of numbers divisible by 3 starting from zero (F1=0, F2=3, F3=6, F4=9, etc.)

Then on E1:

=SUM(OFFSET($D$1,F1,0,3,1))

Drag this formula all the way down.

So you do want to count rather than sum? Your formula will already do that. If it isnt producing the result expected then it suggests that it is failing to count customers you think should be included.

Perhaps this could be the reult of leading/trailing spaces in the A column customer name cells?

You need to check your data. Incidentally, the following will do what your original formula did but it doesnt require array entering:

=SUMPRODUCT--A3:A249=Customer x,--C3:C2490.25

Dear baileyn3, Good Evening.

I built this formula to solve your question.

=SUM(INDIRECT(CONCATENATE("$D"&(ROW()+(ROW()-1)*2)&":"&"$D"&((ROW()+(ROW()-1)*2)+2))))

Put it on E1.
Copy it down simply.

.

What the formula will do is count the number of customers with a value 0.25. If you want to Sum then try this instead doesnt require array entering:

=SUMPRODUCT--A3:A249=Customer x ,--C3:C2490.25,C3:C249