change font color using arguments

[Fred]

Have a spreadsheet with a column for Social Security #.The
person entering the data sometimes repeats the information
(Eg. Social Security # ). Being this is a lengthly
spreadsheet, is it possible to enter a formular that would
change the color(pattern)if the number is repeated(Eg
Cells with the repeat numbers the digits would turn red)

 

[Ron de Bruin]

Try this examples Fred

http://www.cpearson.com/excel/NoDupEntry.htm
http://www.cpearson.com/excel/duplicat.htm

 

[Cecilkumara Fernando]

Fred,
Assumed the column is "F" and F1 has the heading.
select F2:F10000 (F2 should be the active cell)
Format>Conditional Formatting>
in the Conditional Formatting dialog box
change the "cell value is" to "formula is"
and type the following formula
=COUNTIF($F$2:$F$10000,$F2)>1
click Format button and select red form the colour dropdown box
click OK, OK
Cecil

 

[Bob Phillips]

also, if you use the formula
=COUNTIF($F$1:$F1,$F1)>1
in the first cell and copy down as Cecil says, the first instance won't get
highlighted, just subsequent repetitions.

Just another thought.