Using Formula To Detect Duplication Of Invoice Numbers?

May be this link might help?

http://www.mcgimpsey.com/excel/udfs/sequentialnums.html

Originally Posted by Vitucho

Please, somebody
How can I create a formula to detect duplicate invoice number and give a flag or stop to let me know that there is a invoice with the same number already.

Thanks
Vitucho

or try conditional formatting.

select the range which contains invoice numbers (I supposed it is col A).
go to menu Format > Conditional Fomatting...

select Fomula is (instead of defaul Cell value is)
and put following formula in the input box.

=COUNTIF($A$1:$A$500,A1)>1

then press Format... tab and click on Patterns tab and select colour (may be red).
press Ok.

all duplicate values in range will be highlighted.

(range in above formula must be the same that you selected)

hope this would help.

see the attached file for above example.