Does Excel look at every cell in the range while performing calculations?

An array formula like the one in your example will process every cell
referenced in the array, whether they're empty or not.

Some functions will only process the used range. =COUNTIF(A:A,B1)

If your data ends on row 1000 and you use references to row 65336 in an
array formula you're wasting calculation time by having to evaluate all
those empty cells.

Instead of using an arbitrary end of reference to ensure you "get" all the
data use dynamic ranges.

http://contextures.com/xlNames01.html#Dynamic

Biff

"Randy" wrote in message
...
Does Excel look at every cell in the range while performing calculations?
I
have the following array formula and am wondering if it will slow things
down
if I change the 12000s to 65536s. By changing the number I would not have
to
worry about missing any data but then again if it is going to burn my cpu
up
I will leave it as is.

=AVERAGE(IF((SCMatrix!$C2:$C12000="NOW")*(SCMatrix !$Y2:$Y120000),SCMatrix!$Y2:$Y12000))

Thanks!

Randy