How to Use Excel to Find Duplicates in a Long List

1. Open Microsoft Excel and the file that contains your list with duplicates.
2. Highlight the entire column (or columns) that contain the list(s) you want to examine for duplicates by clicking on the column letter(s) ('A,' 'B,' etc.) at the top of your data.
3. Click the 'Conditional Formatting' command in the 'Styles' group under the 'Home' tab, choose 'Highlight Cells Rules' and then choose 'Duplicate Values.'
4. Choose the color scheme you want the duplicate values to be highlighted with using the drop-down menu on the right of the 'Duplicate Values' dialog box that opens, or just click 'OK' to accept the default color scheme and highlight all duplicates.