How to create a warning table when entering duplicate Excel data

How to create a warning table when entering duplicate Excel data is a useful skill for those who regularly work with large and complex spreadsheets. In this article, AnonyViet will guide you how to do that with just a few simple steps.

Why should you create a warning table when entering duplicate Excel data?

Excel is a very useful software in data management and processing. However, during the data entry process, you may encounter duplicate data entry, affecting the quality and accuracy of the information.

To avoid this, you can use the feature to create a warning table when entering duplicate data in Excel. A warning panel will appear when you enter a value that already exists in the data area, helping you recognize and correct errors promptly.

How to create a warning table when entering duplicate Excel data

Step 1: Highlight the list column to create a warning table when entering duplicate data

Step 2: Select the Data tab > Select the icon as shown to access Data Validation

Step 3: In the Allow section, select “Custom”

In the Formula section, enter the formula =COUNTIF(A:A,$A1)=1

Please change column A in the above formula to correspond to the column in your data!

Step 4: Switch to the “Error Alert” tab, fill in the Title and Error Message boxes, for example as shown in the picture

Step 5: Click OK to save

So when you enter duplicate data, Excel will display a warning table as follows:

Epilogue

So I have guided you How to create a warning table when entering duplicate Excel data using formulas and conditional formatting rules. By applying this method, you can control your data entry, avoiding confusion and errors. Hope this article has brought you useful and interesting information. Thanks for watching!