=SUM(N(FREQUENCY(IF(rangeB="X911",MATCH(rangeA,ran geA,0)),MATCH(rangeA,rangeA,0))0))

ctrl+shift+enter, not just enter
the answer returns 4 not 3


"Amber" wrote:

My data contains 2 columns of data

I want to count column A if column B has not already been counted.
A B
1951 X911
2614 X911
2618 X911
2614 X911
1031 X911
2614 X911
2614 WAT
2614 WAT
2614 WAT
2614 WAT
2614 WAT

In other words, I want to see how many different lines of X911. The answer
I want is 3 because there are 3 different numbers associated with X911

HELP!!!!