If you want duplicate values to stand out in an Excel spreadsheet, you can choose between two conditional formatting rules.

You might be tempted to use one of Excel’s built-in conditional format rules (not available in 2003), but it won’t work as expected. It’ll hide each instance of a duplicate value.

You can easily discover the duplicate values in a Microsoft Excel spreadsheet using its conditional formatting duplicate highlighting feature.

Excel’s conditional formatting enables you to use custom formulas to highlight duplicates effectively. By applying a formula, you can flag repeated values in a column with specific colors ...

Excel's conditional formatting lets you formats cells based on the value of those cells or their formulas. Learn the basics of this amazing feature.

It can also indicate which values are duplicates. You can use conditional formatting to compare all manner of values, including numbers, text and dates.