Here are 2 formula's that will both work (Array formulas so commit with
CTRL+SHIFT+ENTER):

1) =SUMPRODUCT(IF(COUNTIF(A1:A20,A1:A20)1,1,0))
2) =SUMPRODUCT(IF(COUNTIF(A1:A20,A1:A20)1,1,0)/COUNTIF(A1:A20,A1:A20))

#1 will count the total number of duplicates, so 1,1,2,3,4,5,5,5 will return 5
#2 will count the total number of UNIQUE duplicates, so 1,1,2,3,4,5,5, will
return 2

Both formulas will return 0 if there are no duplicates.

Just change the A1:A20 reference to match your data.
Does that help?
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Regards,
Dave


"RJ31" wrote:


I have a large complex spreadsheet that calculates just when the file is
saved. I was wondering if anyone new how to ensure that the same number
is not entered twice into a column other than using the find command.
Ryabn


--
RJ31
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