Data validation rules in Google Sheets - Step-by-Step Guide

Introduction

Data validation rules help you control what kind of information can be entered into a cell. This keeps your data clean and avoids mistakes by limiting inputs to certain types or lists.

When you want to allow only numbers between 1 and 100 in a score column.

When you want users to pick a country from a list instead of typing it.

When you want to prevent empty cells in a required field.

When you want to allow only dates after today in a deadline column.

When you want to restrict entries to whole numbers only.

Steps

Step 1: Select the cell or range where you want to apply data validation

- Google Sheets grid

The selected cells are highlighted

Step 2: Click Data

- top menu bar

The Data menu dropdown opens

Step 3: Select Data validation

- Data menu dropdown

The Data validation pane appears on the right side

Step 4: Choose the criteria type from the Criteria dropdown

- Data validation pane

Options like List from a range, List of items, Number, Text, Date, Checkbox appear for selection

💡 Pick 'List of items' to type your own list separated by commas

Step 5: Set the specific rule details based on your criteria choice

- Data validation pane

Input fields appear to enter numbers, dates, or list items

Step 6: Check or uncheck 'Show dropdown list in cell' if available

- Data validation pane

A dropdown arrow appears in the cell for list selections if checked

Step 7: Choose what happens on invalid data by selecting 'Show warning' or 'Reject input'

- Data validation pane

Invalid entries either show a warning or are blocked

Step 8: Click Save

- Data validation pane

The rule is applied and the pane closes

Before vs After

Before

Column A allows any text or numbers, users enter inconsistent country names like 'USA', 'us', 'United States'

After

Column A only allows selection from a dropdown list with 'USA', 'Canada', 'Mexico', preventing typos

Settings Reference

Criteria

📍 Data validation pane

Defines the type of data allowed in the cell

Default: List from a range

Show dropdown list in cell

📍 Data validation pane

Shows a dropdown arrow for easy selection when using lists

Default: Checked for list criteria

On invalid data

📍 Data validation pane

Controls whether invalid data is blocked or just warned about

Default: Show warning

Appearance

📍 Data validation pane

Displays a message to guide users on what to enter

Default: Unchecked

Common Mistakes

Not selecting the correct cell range before applying validation

The rule applies only to selected cells, so other cells remain unrestricted

Always select the exact cells you want to control before setting data validation

Choosing 'Show warning' but expecting invalid data to be blocked

Show warning lets users enter invalid data but flags it, it does not stop entry

Select 'Reject input' to block invalid entries completely

Typing list items with spaces after commas causing extra spaces in dropdown

Extra spaces become part of the list items and confuse users

Type list items without spaces after commas, like 'Red,Green,Blue'

Summary

Data validation rules control what users can enter in cells to keep data clean.

You can limit entries by number, date, list, or custom formulas.

Choose to warn or block invalid data and optionally show dropdown lists for easy selection.

Practice

1. What is the main purpose of Data validation rules in Google Sheets?

easy

A. To control what users can enter in cells to keep data clean

B. To automatically calculate sums and averages

C. To change the color of cells based on values

D. To create charts from data

Solution

1. Step 1: Understand what data validation does

   Data validation sets rules that limit what users can type or select in cells.

2. Step 2: Compare options to the purpose

   Only To control what users can enter in cells to keep data clean describes controlling user input to keep data clean, which is the main goal.

3. Final Answer:

   To control what users can enter in cells to keep data clean -> Option A

4. Quick Check:

   Data validation = control input [OK]

Hint: Data validation controls input, not calculations or colors [OK]

Common Mistakes:

• Confusing data validation with formulas
• Thinking it changes cell colors
• Assuming it creates charts

2. Which of these is the correct way to set a data validation rule for a cell to only allow numbers between 1 and 10?

easy

A. Select the cell, go to Data > Data validation, choose 'Number' and set 'between' 1 and 10

B. Type =IF(A1>0, "Valid", "Invalid") in the cell

C. Use conditional formatting to highlight numbers between 1 and 10

D. Enter a formula =AND(A1>=1, A1<=10) directly in the cell

Solution

1. Step 1: Identify how to set data validation

   Data validation rules are set via the Data menu, not by typing formulas in cells.

2. Step 2: Match the correct method

   Select the cell, go to Data > Data validation, choose 'Number' and set 'between' 1 and 10 correctly describes using Data > Data validation and setting number between 1 and 10.

3. Final Answer:

   Select the cell, go to Data > Data validation, choose 'Number' and set 'between' 1 and 10 -> Option A

4. Quick Check:

   Data validation set via menu = Select the cell, go to Data > Data validation, choose 'Number' and set 'between' 1 and 10 [OK]

Hint: Set rules via Data menu, not by typing formulas [OK]

Common Mistakes:

• Trying to type validation formulas in cells
• Confusing conditional formatting with validation
• Using formulas that only display text, not restrict input

3. You set a data validation rule on cell A1 to allow only dates after 2023-01-01. What happens if a user tries to enter '2022-12-31'?

medium

A. The entry is accepted without any warning

B. The cell automatically changes the date to 2023-01-02

C. Google Sheets shows an error and prevents the entry

D. The cell highlights the date but allows the entry

Solution

1. Step 1: Understand data validation behavior for invalid input

   When a user enters data that breaks the validation rule, Sheets shows an error and blocks the entry by default.

2. Step 2: Apply this to the date rule

   Since '2022-12-31' is before '2023-01-01', the entry is invalid and will be rejected with an error.

3. Final Answer:

   Google Sheets shows an error and prevents the entry -> Option C

4. Quick Check:

   Invalid input triggers error and blocks entry [OK]

Hint: Invalid input triggers error and blocks entry by default [OK]

Common Mistakes:

• Thinking invalid data is accepted silently
• Assuming automatic correction of invalid data
• Confusing highlighting with blocking input

4. You created a data validation rule to allow only text from a list: 'Apple', 'Banana', 'Cherry'. But users can still enter 'Orange'. What is the likely mistake?

medium

A. The list was entered as plain text in the cell, not as a range or list in validation

B. The validation rule was set to 'Show warning' instead of 'Reject input'

C. The cell was formatted as Number instead of Plain text

D. The sheet was not saved after setting the rule

Solution

1. Step 1: Check validation settings for handling invalid input

   Data validation can either reject invalid input or just show a warning but allow it.

2. Step 2: Identify why 'Orange' is accepted

   If 'Show warning' is selected, invalid entries like 'Orange' are allowed with a warning, explaining the issue.

3. Final Answer:

   The validation rule was set to 'Show warning' instead of 'Reject input' -> Option B

4. Quick Check:

   Show warning allows invalid input [OK]

Hint: Use 'Reject input' to block wrong entries, not just warn [OK]

Common Mistakes:

• Confusing warning with blocking input
• Not checking validation input handling option
• Assuming formatting controls validation

5. You want to create a data validation rule that allows users to select only weekdays (Monday to Friday) from a date picker in cell B2. Which custom formula should you use in the data validation rule?

hard

A. =OR(WEEKDAY(B2) = 1, WEEKDAY(B2) = 7)

B. =B2 >= DATE(2023,1,1)

C. =WEEKDAY(B2) > 5

D. =AND(WEEKDAY(B2) >= 2, WEEKDAY(B2) <= 6)

Solution

1. Step 1: Understand WEEKDAY function output

   WEEKDAY returns 1 for Sunday, 2 for Monday, ..., 7 for Saturday.

2. Step 2: Identify weekdays range

   Weekdays are Monday (2) through Friday (6), so the formula must check if WEEKDAY is between 2 and 6.

3. Step 3: Match formula to condition

   =AND(WEEKDAY(B2) >= 2, WEEKDAY(B2) <= 6) uses =AND(WEEKDAY(B2) >= 2, WEEKDAY(B2) <= 6), which correctly allows only weekdays.

4. Final Answer:

   =AND(WEEKDAY(B2) >= 2, WEEKDAY(B2) <= 6) -> Option D

5. Quick Check:

   Weekdays = WEEKDAY 2 to 6 [OK]

Hint: WEEKDAY 2-6 means Monday to Friday [OK]

Common Mistakes:

• Using wrong WEEKDAY numbers for weekdays
• Allowing weekends by mistake
• Not using AND to check range