Tips & Tricks 1 – A List is Unique or Not (Whether it has duplicates)

Assuming, your list is in A1 to A1000. Use following formula to know if list is unique.

=MAX(FREQUENCY(A1:A1000,A1:A1000))

=MAX(INDEX(COUNTIF(A1:A1000,A1:A1000),,))

If answer is 1, then it is Unique. If answer is more than 1, it is not unique.