What is the purpose of Data Validation in Excel?

Microsoft Excel - Interview Questions and Answers

What is Data Validation in Excel?

Data Validation in Excel is a feature that helps control and restrict the type of data entered into a cell. It ensures accuracy and consistency by allowing only predefined values or formats.

Purpose of Data Validation

* Prevent Invalid Data Entry – Restrict users from entering incorrect values.
* Ensure Data Consistency – Standardize inputs like dates, numbers, or text formats.
* Improve Data Entry Efficiency – Guide users with dropdown lists or error messages.
* Enhance Accuracy – Minimize errors in calculations and reports.

How to Apply Data Validation

Select the Cell(s) or Range
- Click on the cell(s) where you want to apply validation.
Open the Data Validation Menu
- Go to the Data tab → Click Data Validation in the "Data Tools" group.
Choose Validation Criteria
- Under the Settings tab, select from different validation types:
  - Whole Number (Restrict to whole numbers only)
  - Decimal (Allow only decimal values)
  - List (Create a dropdown menu)
  - Date (Restrict to specific date ranges)
  - Time (Set allowed time frames)
  - Text Length (Limit characters in text)
  - Custom (Use formulas for complex rules)
Set Conditions
- Enter the allowed range or values (e.g., min/max for numbers, a date range, etc.).
Add Input Message (Optional)
- Under the Input Message tab, provide instructions that appear when users select the cell.
Add an Error Alert (Optional)
- Under the Error Alert tab, customize a warning message if users enter invalid data.
Click OK to Apply.

Examples of Data Validation

1. Create a Dropdown List

Select cells (A1:A10).
Open Data Validation → Choose List.
Enter values like:
```
Apple, Banana, Orange
```
Click OK → A dropdown menu will appear in the selected cells.

2. Restrict Numbers Between 1 and 100

Select a cell.
Open Data Validation → Choose Whole Number.
Set Minimum: 1, Maximum: 100.
Click **OK`.

3. Restrict Dates to a Specific Range

Select a cell.
Open Data Validation → Choose Date.
Set the start date as 01/01/2024 and the end date as 12/31/2024.
Click OK.

4. Allow Only Email Format (Using Custom Formula)

Open Data Validation → Choose Custom.
Enter formula:
```
=ISNUMBER(SEARCH("@", A1))
```
Click OK → Only entries containing "@" will be allowed.

How to Remove Data Validation

Select the cell(s).
Go to Data → Data Validation.
Click Clear All → OK.

What is Data Validation in Excel?

Purpose of Data Validation

How to Apply Data Validation

Select the Cell(s) or Range

Open the Data Validation Menu

Choose Validation Criteria

Set Conditions

Add Input Message (Optional)

Add an Error Alert (Optional)