Hi,
if you have 6000 rows what he means is to copy the formula from B1 all the
way down to B6000. How you do that two ways

1 select the cell where the formula is, right click on the mouse, copy, then
go one cell down, highlight from there to the last row where you see
information in column A, right click on the mouse, paste

2 having the cell with the formula highlighted, move the mouse to the right
bottom corner untill you see a bold cross like this +, when you see it
double click in the mouse, it will copy the formula down up to it find a
blank in the adjacent column in your case column A

"rock" wrote:



Sorry to be so newby Bob, but when you say 'copy' down, what exactly do
you mean?

I have entered the formula in B1 but..


Thanks


rock





Bob Phillips wrote:
Assuming the data is in column A, add a formula in column B of

=IF(COUNTIF($A$1:$A1,$A1)1,"Duplicate","")

Cpy that down, then you can filter column B for Duplicate