Formula needed to tell me if a value exists

Originally Posted by WhatF

Hi,

I have a sheet with a column of ID Numbers (Column C)
I need a formula in the next column (Column D) to inform me if the new ID Number which I'm entering now is already existing somewhere in column C.

example:

Column C -----Column D
ID Number
105235 --------the needed formula
125435 --------the needed formula
145298 --------the needed formula
548694 --------the needed formula
125435 --------the needed formula should tell me that this ID exists

In the example, I entered the new ID number 125435 after the last ID number in column C, the formula in column D (in the same row as the newely eneterd ID)should inform me that it exists in row 3 as shown

How can I do that?

Thank you

Hi,
Try data validation:
http://www.cpearson.com/excel/NoDupEntry.aspx

Or conditional formatting:
http://www.contextures.com/xlCondFor...html#DupColumn

Or if you want a formula....

In D2...

=IF(Countif(C$2:C2,C2)>1,"Repeat","") copied down...