Highlight duplicate values

Note: Excel contains many built-in "presets" for highlighting values with conditional formatting, including a preset to highlight duplicate values. However, if you want more flexibility, you can highlight duplicates with your own formula, as explained in this article. If you want to highlight cells that contain duplicates in a set of data, you can use a simple formula that returns TRUE when a value appears more than once. For example, if you want to highlight duplicates in the range B4:G11, you can use this formula: =COUNTIF($B$4:$G$11,B4)>1 Note: with conditional formatting, it's important that the formula be entered relative to the "active cell" in the selection, which is assumed to be B4 in this case.