Data Validation is a powerful feature of Excel used for improving data accuracy by controlling the input type. For example, if a user should only enter a date between January and December 2025, or restrict a score entry to only integers between 0 and 100, Data Validation ensures such rules are followed.
Steps to apply Data Validation:
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Select the cell or range.
Go to Data Tab → Data Validation.
Under the Settings tab, define criteria (e.g., Whole number between 1 and 100).
Use Input Message tab to provide guidance.
Use Error Alert tab to define messages on wrong input.
Error Alert Tab has 3 alert types:
Stop: Prevents entry of invalid data.
Warning: Allows entry with a caution message.
Information: Simply informs about the invalid entry.
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It ensures that users understand what kind of values are acceptable, thereby reducing errors and improving spreadsheet reliability.