Prevent duplicates before they happen by combining a simple function with data validation.

Excel's data validation feature is more versatile than you might think. Learn how to use literal values, input values, list values, and even formulas to restrict input date values using data ...

A common use of data validation is to create a drop-down list. Use it to restrict the type of data that users enter into an Excel cell.

Learn how to create a drop-down list using Data Validation in Excel. Data Validation limits the type of data that can be entered into a cell.