Data Validation: Control What Users Can Enter

Why Use Data Validation?

• Prevent data entry errors
• Ensure consistency across entries
• Guide users with clear input requirements
• Improve overall data quality

Accessing Data Validation

Go to Data tab > Data Validation

Validation Types

Type	Use Case
Whole Number	Restrict to integers within a range
Decimal	Allow decimals within a range
List	Create dropdown from predefined options
Date	Restrict to specific date range
Text Length	Limit character count
Custom	Use formula for complex rules

Creating a Dropdown List

1. Select the cells for the dropdown
2. Go to Data > Data Validation
3. Set Allow to "List"
4. Enter items or select a range as Source

Input and Error Messages

• Input Message: Displays when the cell is selected
• Error Alert: Displays when invalid data is entered

Custom Formula Examples

• =A1>B1 (A must be greater than B)
• =ISNUMBER(A1) (must be a number)
• =LEN(A1)<=10 (max 10 characters)

Conclusion

Data validation is essential for maintaining data integrity in shared workbooks.