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

When you update this spreadsheet with new or different data, you won’t have to re-create the validation rule, but you will need to click Circle Invalid Data again. This tool would be useful to bring ...

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.

I've got an Excel 97 worksheet in which I need to validate some cells. No problem, I'll just use Data->Validate, right? Wrong. The built in validation works well enough as long as the user doesn't ...