one way:

Select your range (assume column A, with A1 active):

Choose Data/Validation:

Allow: Custom
Formula: =AND(ISNUMBER(A1), A1<10000000000, A1=0, INT(A1)=A1,
COUNTIF(A:A,A1)<2)


In article ,
SiH23 wrote:

Hi,

I am trying to add validation that willl do the following:

1. Prevent duplicate values being entered into a cell.
2. Only allow a 10 digit number being entered into a cell.

I know how to add these methods individually, but is it possible to set both
validation principles together on a cell or range of cells?

I would be most grateful for any help provided.

Many thanks,

John.