Quickly prevent duplicate entries in a column in Excel

When it comes to prevent or avoid duplicate entries in a column, we may consider the function of Data Validation in Excel. But using the Date Validation to prevent duplicate entries in a column, you may need to spend some time on how to get it work first. However, with the Prevent Duplicate entries utility of Kutools for Excel, you can easily prevent duplicate entries in a column in Excel.

Prevent duplicate entries in a whole column

Prevent duplicate entries in a range of the column

Prevent Duplicate demo

Prevent duplicate entries in a whole column

Click Kutools >> Prevent Typing >> Prevent Duplicate, see screenshot:

Usage:

1. Select a single column that you want to prevent duplicate entries.

2. And then apply the utility by clicking Kutools > Prevent Typing > Prevent Duplicate, a dialog pops out to remind you it will remove Data Validation in your selected range if continue the operation. See screenshot:

3. Click Yes to continue, and a dialog pops out to remind you the selected range has been prevented typing duplicates. See screenshot:

4. Click OK, from now, when you try to type in the same data in the same column, you won’t be allowed. See screenshot:

Tip: if you have not selected a single column before applying the utility, then the column of the active cell will be set to prevent duplicate entries.

Prevent duplicate entries in a range of the column

Click Kutools >> Prevent Typing >> Prevent Duplicate, see screenshot:

Usage:

1. Select the range in the column which you want to avoid duplicate entries, see screenshot:

2. Click Kutools >  Prevent Typing > Prevent Duplicate, and click Yes > OK in the popping out dialogs to continue the operation. See screenshot:

when you type the same data into this selected range, a dialog is displayed to remind you the value you type is invalid. See screenshot:

If you type the same data out of the selected range in the column, it is valid, see screenshot:

Note:

This function supports undo (Ctrl + Z).

Demo: prevent duplicate entries in a column in Excel