Prevent Repeating Data Entry

R

Ryan

Howdy,

I need a way to prevent a user from entering duplicate data in a range of
cells (ex. C6:C36). I need to prevent the user from entering an invoice
number twice. I don't know if this is something for Data Validation or not. I
have been trying that and cant get it to work.
 
B

Bernie Deitrick

Ryan,

Select C6:C36, the use Data / Validation... on the "Settings" tab, Select Custom under "Allow"
and use the formula

=COUNTIF($C$6:$C$36,C6)=1

HTH,
Bernie
MS Excel MVP
 
R

Ryan

Thanks a lot, thats helped out alot

Bernie Deitrick said:
Ryan,

Select C6:C36, the use Data / Validation... on the "Settings" tab, Select Custom under "Allow"
and use the formula

=COUNTIF($C$6:$C$36,C6)=1

HTH,
Bernie
MS Excel MVP
Click to expand...
 
D

DocBrown

What If I already have validation Allow=List AND I want to detect duplicates
in range say H13:H20

Validation:
Allow: List
Source: =AccountList

John
 
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