Sum from last row - 'x' (Excel 2003)

[newb]

I thought I could figure out a simple array formula to accomplish this, but find it harder than I thought. Conditionally, I want to sum rows in a column, starting with the last row and summing backwards a number of rows based on that condition. I have an attachment as an example. Is this possible without VBA?

[HansV]

You write "If count > 7 then sum last cell through (last cell - 7)" but your example formula uses "sum last cell through (last cell - 6)". Similar for if the count is 7 or less.

Assuming that your example formulas indicate what you want, you could use
<code>
=SUM(IF(COUNT(A:A)>7,OFFSET(A1,COUNT(A:A)-6,0,7),OFFSET(A1,COUNT(A:A)-2,0,3)))
</code>
This is a 'normal' formula, not an array formula.
It assumes that there are no blanks in the range from A1 to the last filled cell in column A.

[bosco_yip]

IF there are blank cells inside the range of column A, you can consider to use :

=SUM(INDEX(A:A,MATCH(9.9E+307,A:A)-IF(COUNT(A:A)>7,6,2)):INDEX(A:A,MATCH(9.9E+307,A:A )))

Regards
Bosco