Originally Posted by EricLeung
Whenever input data in one cell in a worksheet, how can Excel help to check if this entry (data) has never been input before after inputting the data, so that I can be sure what I have just entered have never appreared before.
Please can anyone suggest any formula / function / code which can help.
Thanks & Regards,
Assuming your list is in column A, use the following formula in column B from the second item in the list down.
=IF(ISERROR(VLOOKUP($A2,$A$1:$A1,1,FALSE)),"Unique ","Already Used")
If you copy that down the list the formula will adjust itself as it goes.