How to highlight cell if value duplicate in same column for google spreadsheet?

Question

I am looking for formula for google spreadsheet highlight cell if value duplicate in same column

can anyone please assist me for this query?

Answer 1

Answer of @zolley is right. Just adding a Gif and steps for the reference.

1. Goto menu Format > Conditional formatting..
2. Find Format cells if..
3. Add =countif(A:A,A1)>1 in field Custom formula is
   • Note: Change the letter A with your own column.