Prevent Duplicate Values in a Range in Excel

Add to Favorites
Author: | Edits: don

Ensure that your lists and data sets are full of only unique values by preventing a user from inputting duplicate values into a range in Excel.

This is a great tip that uses data validation in order to ensure a unique data set and I will also cover how to show the user a custom error message so that they will know what they did wrong if they try to enter a duplicate value and also a custom input message so that the user will know, before they try to input a value, that it must be unique.

Data validation is a very powerful tool in Excel and this tutorial focuses on a custom data validation rule that, though a little tricky, is covered thoroughly and is not too difficult to follow and change for your needs.

After this tutorial, you should be ready to go on your own and make custom data validation rules that work for you specific data set.

I hope you enjoy this tutorial!

Downloadable Files: Excel File

Question? Ask it in our Excel Forum

Our Excel Courses

  • Skill Level: All Levels
  • |
  • 5 hours+

How to make a fully featured professional form in Excel that is unbreakable. This includes how to use the form to store, view, edit, and delete data from a data storage worksheet.

  • Skill Level: All Levels
  • |
  • 2 hours

Send Emails from Excel using VBA and Macros. This course starts from the Basics and builds up to more advanced examples with attaching workbooks, worksheets, PDF's, automatically sending emails, including a signature, error handling, increasing speed, and more.

Similar Content on TeachExcel
Prevent Duplicate Values in Excel
Tutorial: I show you how to prevent duplicate values being entered into Excel using Data Validation...
Show All Formulas in a Worksheet in Excel
Tutorial: Display all formulas instead of their output values. This allows you to quickly troubles...
Highlight, Sort, and Group the Top and Bottom Performers in a List in Excel
Tutorial: How to highlight the rows of the top and bottom performers in a list of data. This allows...
Easily Compare Duplicate Values in Excel
Tutorial: Here, I'll show you a simple technique to quickly and easily compare large lists of duplic...
Highlight Duplicate Values in Excel
Tutorial: How to highlight duplicate values in a list. Also, how to arrange those values next to ea...
Count the Occurrences of the Largest or Smallest Value in a Range
Tutorial: How to count the occurrence of the largest or smallest value in a range; basically, how m...