I want to be prompted for an entry that already exists in excel

[Jade]

I use Excel to maintain an animal breeding program. I want to be prompted
when a animal number is entered that already exists. This would be handy for
name and address databases too.

[Jan Karel Pieterse]

Hi Jade,

> I want to be prompted
> when a animal number is entered that already exists.
>

Use Data, validation for this.

- select the range that will get the numbers (lets say the entire
Column A)
- Choose Data, validation
- Click the dropdown box and select "Custom"
- enter this formula:
=COUNTIF(A1:$A$1,A1)<2

(notice the dollar signs!)

Regards,

Jan Karel Pieterse
Excel MVP
www.jkp-ads.com