hi,

put this formula in Book1 cell B1 then fill down
=COUNTIF('[Book2.xlsx]Sheet1'!$A:$A,A1)

do the same thing in Book2
=COUNTIF('[Book1.xlsx]Sheet1'!$A:$A,A1)

results = 0 means sole postcode

isabelle

Le 2015-03-03 11:19, a écrit :
Hi all,

I wonder if anyone can help me, I'm an excel nightmare and have a task which will allow me to work much more efficiently .

I have 2 excell documents both containing approx 500,000 postcodes and need to see which postcodes appear in both lists.

Thanks :)