Check out this web page of Chip Pearson:

http://www.cpearson.com/excel/NoDupEntry.htm
--
HTH,

RD
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Please keep all correspondence within the Group, so all may benefit!
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"Courtneyf04" wrote in message
...
I am trying to create a formula that we warn me when I enter a number that
has already been entered. I have a

column of Product Id numbers and don't want to enter in duplicate numbers.
Any help for anyone is greatly

appreciated - Thanks!