How to Identify Duplicate Items in Excel

1. Click on the column name that you want to check for duplicates. You can also select a range across several columns by selecting the top-left cell in the range and then holding 'Shift' while selecting the bottom-right cell.
2. Select the 'Home' tab at the top of the Excel window. Click on the 'Conditional Formatting' button in the 'Styles' area of the ribbon.
3. Move your mouse over 'Highlight Cell Rules' in the drop-down menu and then choose 'Duplicate Values.'
4. Choose the type of color to apply to duplicate cells by using the drop-down box on the right. It defaults to a light red color with red text but you can quickly change it to yellow, green or you can create a custom look by choosing 'Custom Format.' Click 'OK' when you are done and all the duplicate cells will be highlighted.