Excel Data Validation

Data validation in Microsoft Excel is a feature that allows you to control and restrict the type and value of data that users can enter into a cell. It helps ensure that the data entered into your worksheet is accurate, consistent, and meets specific criteria. Here's how you can use data validation in Excel:

Select the cell or range of cells where you want to apply data validation.

Go to the "Data" tab in the Excel ribbon.

Click on the "Data Validation" button in the "Data Tools" group. The Data Validation dialog box will appear.

In the "Settings" tab, you can specify the validation criteria:

Allow: Choose the type of data you want to allow, such as whole numbers, decimal numbers, dates, times, text length, etc.

Data: Set the specific criteria for the selected data type. For example, if you choose "Whole number," you can specify a range of values or a list of allowed values.

Input Message (optional): Provide a custom message that will be displayed when a user selects the cell.

Error Alert: Define the error message and style to be displayed if the entered data violates the validation rules.

Click on the "OK" button to apply the data validation rules to the selected cells.

Once data validation is set up, Excel enforces the rules you defined. If a user tries to enter data that doesn't meet the criteria, an error message will be displayed, and the entry will be rejected until valid data is entered.

Data validation can be useful in various scenarios, such as ensuring numeric data falls within certain limits, restricting input to a predefined list of options, or enforcing specific date or time formats.

Note that data validation is not foolproof, as it only prevents direct user input. It does not prevent data from being pasted or imported into the worksheet, nor does it prevent data from being edited programmatically or through Excel's built-in features.