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Indentation Error in Python: Solving One of the Most Common Syntax Errors!

Indentation Error in Python: Solving One of the Most Common Syntax Errors!

Q: 1. How can I detect if I have mixed spaces and tabs in my Python code?

Most modern code editors offer a "Show Invisibles" feature, which visualizes spaces and tabs. Enabling this feature allows you to spot mixed indentation instantly. Alternatively, you can use linters like Flake8 or Pylint, which highlight indentation issues, including the mixing of spaces and tabs, to help you clean up your code before running it.

Q: 2. What is the difference between using spaces and tabs for indentation in Python, and which is better?

Python allows both spaces and tabs for indentation, but it's essential to stick to one. Using spaces is generally recommended, as it’s the PEP 8 standard and is more widely supported across different editors. Tabs can cause inconsistencies, especially when developers with different IDE settings work together. Spaces ensure consistency and make the code more portable.

Q: 3. Can indentation errors cause runtime errors in Python, or do they only affect the code’s structure?

Indentation errors in Python typically affect the structure of your code, causing SyntaxErrors rather than runtime errors. These errors prevent your code from executing properly. The interpreter relies on indentation to understand the code’s logical structure, so even a minor indentation mistake will cause Python to fail in parsing the code.

Q: 4. How do I fix an indentation error in a large codebase with multiple nested loops?

Fixing indentation errors in large codebases can be tricky, but you can make it easier by using the auto-formatting feature in your IDE or editor. For example, in VS Code, pressing Shift + Alt + F auto-formats the code to correct indentation issues. Additionally, enabling line-by-line indentation guides can help you visually track nested levels.

Q: 5. What should I do if my Python code works fine in one IDE but shows indentation errors in another?

This issue usually arises from mismatched editor settings regarding spaces and tabs. Check both IDEs’ settings to ensure they are configured to use spaces for indentation and match the tab width (usually 4 spaces). You can also try reformatting the code in your current IDE and check if the problem persists after making those adjustments.

Q: 6. Is there a Python-specific tool or plugin to automatically fix indentation issues?

Yes, there are several tools like Black, a Python code formatter, that automatically fix indentation issues according to PEP 8 standards. Black reformats your code, including fixing indentation, ensuring that it follows consistent style and spacing. Integrating it into your workflow ensures that indentation issues are caught and resolved automatically.

Q: 7. Can indentation errors affect the logic of my Python code?

Indentation errors don't directly affect the logic of your code but can change its structure, making it behave unexpectedly. For instance, an if statement with incorrect indentation could result in code that doesn’t run as expected or leads to unintended behavior, as Python interprets the block incorrectly.

Q: 8. How do I avoid indentation errors when collaborating with other developers on the same Python project?

The best approach is to establish a coding standard early, ensuring that everyone uses spaces (preferably 4 spaces) for indentation. Configure your editors to insert spaces instead of tabs, and regularly run a linter to enforce these standards. Tools like Prettier or Black can auto-format code on commit, helping maintain consistency across contributors.

Q: 9. Why does Python raise an IndentationError for a single misplaced space or tab?

Python’s reliance on indentation for defining blocks of code means that a misplaced space or tab can disrupt the interpreter’s ability to understand the structure of your program. Even a minor deviation, such as an extra space at the beginning of a line, will cause an IndentationError because Python expects consistent indentation throughout a code block.

Q: 10. Can an IndentationError be caused by copy-pasting code into an IDE?

Yes, when you copy-paste code from different sources, there’s a risk of introducing inconsistent indentation. Some sources may use spaces while others use tabs. To avoid this, always paste code into your editor first and format it using the auto-indent feature, or reformat the pasted code using a tool like Black to correct the indentation.

By Rohit Sharma

Updated on Jun 27, 2025 | 14 min read | 37.1K+ views

Table of Contents

View all

What is an Indentation Error in Python? A Complete Guide
What Are Some of the Common Indentation Errors in Python?
How to remove Indentation Errors in Python Code?
Benefits and Challenges of Using Indentation in Python
How can upGrad help you in Mastering Indentation in Python?

Did You Know? According to a study by the University of Cambridge, syntax errors account for a substantial portion of debugging time in software development. This means that developers often spend a significant amount of time fixing mistakes, such as indentation errors, before they can address more profound logic or runtime issues in their Python code.

An indentation error in Python refers to the use of spaces or tabs to define the structure of your code. You will get an error message if there's inconsistent or missing indentation. As a Python programmer, it can be frustrating to have your project come to a standstill due to an error in your code.

Since Python is one of the most popular programming languages today, it is essential to learn how to resolve an indentation error in Python. This way, you can reduce the time spent on debugging code.

In this blog, you'll learn about the causes of these errors, and how you can solve them using best practices.

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What is an Indentation Error in Python? A Complete Guide

Indentation is a fundamental aspect of Python's syntax, and it helps define blocks of code. Python uses indentation (spaces or tabs) to signify the beginning and end of these blocks. This approach makes Python code more readable and easier to maintain.

An Indentation Error in Python occurs when the indentation in your code is inconsistent or incorrect.

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Understanding Indentation Error in Python With an Example

In Python, a block of code refers to a group of statements that are executed together. These blocks typically correspond to the body of functions, loops, conditionals, and classes. The indentation level determines which statements belong to a particular block.

For example, in an if statement, the indented code directly beneath it forms the block of code that will execute if the condition is True. Similarly, in a loop, the indented code inside the loop is executed for each iteration.

Sample Code:

def greet(name):
    print("Hello,", name)  # This is part of the block inside the greet function

if True: 
    print("This code is inside an if block")  # Indented to be part of the if block
    print("This is also part of the if block")

indentation example in Python, the print() statements are indented to show that they are part of the respective blocks — the greet() function and the if statement.

Indentation Error in Python: An indentation error in Python occurs when the indentation of the code does not follow the rules that Python expects. Such an error typically happens when:

The Python developer incorrectly indents a block of code.
There is inconsistent use of spaces and tabs.
Indentation is missing or excessive.
Since Python uses indentation to define code structure, any mistake in this indentation can prevent the program from running correctly.

The error message typically looks like this:

IndentationError: expected an indented block

Here’s a typical indentation example in Python leading to an error:

Example 1: Unexpected Indentation Error

def greet(name):
print("Hello,", name)  # This will raise an IndentationError

Explanation: In this indentation example in Python above, the print() statement is not indented inside the function greet(). Python expects the body of the function to be indented, so this causes an IndentationError.

Error Message:

makefile

IndentationError: expected an indented block

How to Fix: You need to indent the print() statement to indicate that it is part of the function body.

Fixed Code:

def greet(name):
    print("Hello,", name)  # Indented properly to be part of the function

Example 2: Inconsistent Use of Tabs and Spaces

def greet(name):
    print("Hello,", name)  # Indented with 4 spaces
	print("Welcome!")        # Indented with a tab (inconsistent)

Explanation: In the above indentation example in Python, the first print() statement is indented with spaces, but the second one uses a tab character for indentation. Python requires consistency in indentation, and mixing tabs and spaces leads to an indentation error in Python.

Error Message:

TabError: inconsistent use of tabs and spaces in indentation

How to Fix: You should choose either spaces or tabs for indentation and stick to that choice consistently. Python's style guide, PEP 8, recommends using 4 spaces per indentation level.

Fixed Code:

def greet(name):
    print("Hello,", name)  # Indented with 4 spaces
    print("Welcome!")        # Correctly indented with 4 spaces

Indentation is crucial in Python, as it defines how the program's code is structured and executed. By being mindful of potential issues, you can avoid common pitfalls such as an indentation error in Python. In the following section, you can get acquainted with some common Python indentation errors you need to avoid while writing codes.

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Also Read: Top 10 Reasons Why Python is So Popular With Developers in 2025

Next, let’s look at some of the common indentation errors in Python.

What Are Some of the Common Indentation Errors in Python?

Python relies on indentation to define the structure of code, which makes it a powerful tool for readability. However, improper indentation can cause errors in its classes or libraries that are often hard to identify.

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Here are some common instances of indentation errors in Python that developers encounter:

1. Unexpected Indent

An Unexpected Indent occurs when there is an extra level of indentation where it is not expected, typically after a non-indented line.

Cause: This error happens when you incorrectly add an indentation before a statement that Python does not expect to be indented.

Example:

print("Hello, World!")
    print("This will cause an IndentationError")  # Unexpected indent

Explanation: In this indentation example in Python, the second print statement is indented unnecessarily, which Python does not expect at the top level of the code.

How to Fix: Remove the extra indentation so the second print statement aligns with the first one.

Fixed Code:

print("Hello, World!")
print("This will work fine now")

2. Inconsistent Use of Tabs and Spaces

In Python, you must be consistent when using indentation. Mixing spaces and tabs within the same file will cause an indentation error in Python, as Python can't differentiate between the two, leading to unexpected behavior.

Cause: This happens when a developer uses both tabs and spaces interchangeably within the same block of code. Python interprets them differently, causing misalignment.

Example:

def greet():
	print("Hello")  # Indented with a tab
    print("Hi there!")  # Indented with spaces

Explanation: In this indentation example in Python, the first line uses a tab character to indent, while the second line uses spaces. This inconsistency will throw an IndentationError.

How to Fix: To avoid indentation error in Python, configure your editor to use either tabs or spaces and ensure the entire file uses one method.

Fixed Code:

def greet():
    print("Hello")  # Indented with 4 spaces
    print("Hi there!")  # Consistent indentation with 4 spaces

Also Read: Round function in Python [2025] - Explained for Beginners

3. Unintended Indentation or Lack of Indentation in Specific Contexts

Unintended Indentation can happen when a developer accidentally indents a line of code that should not be indented. Similarly, a lack of indentation can occur when a block of code that should be indented isn't. Both indentation errors are common when writing conditional statements, loops, or functions.

Cause: Unintended indentation typically occurs when a new line of code is mistakenly indented. It can also happen when indentation is missing where it's needed (for example, in a function body or a loop).

Example 1: Unintended Indentation (Missing Code Block)

if x > 10:
print("x is greater than 10")  # Missing indentation after if statement

Explanation: In this indentation example in Python, Python expects the print() statement to be indented as part of the if block. Without the indentation, an indentation error in Python is created.

How to Fix: Indent the print() statement properly so it belongs to the if block.

Fixed Code:

if x > 10:
    print("x is greater than 10")  # Proper indentation

Example 2: Unintended Lack of Indentation (Inside a Function)

def greet():
print("Hello")  # Missing indentation for code inside function

Explanation: Here in this indentation example in Python, the print() statement inside the greet() function should be indented to indicate that it belongs to the function's body. Without indentation, Python doesn't recognize it as part of the function.

How to Fix: Indent the print() statement properly inside the function.

Fixed Code:

def greet():
    print("Hello")  # Proper indentation inside function

By understanding the common types of indentation errors and following these troubleshooting tips, you can keep your Python code clean and error-free. You can also check out some indentation examples in Python to develop a clearer understanding.

Also Read: Top 7 Data Types of Python | Python Data Types

Next, you will learn how to solve common indentation errors in Python.

How to remove Indentation Errors in Python Code?

Indentation errors in Python can be frustrating, but you'd be pleased to know they can be easily solved by following some best practices. Below are some recommendations and tips to help you maintain consistent indentation and avoid common mistakes.

1. Choose a Standard Indentation Style

Spaces vs. Tabs: Decide whether to use spaces or tabs for indentation and stick to one choice throughout your code.

Recommendation: It's best to use 4 spaces for indentation.

Example (using 4 spaces for indentation):

def greet():
    print("Hello, World!")  # Indented with 4 spaces
    print("How are you?")

2. Configure Your Editor to Use Spaces Instead of Tabs

Most modern text editors and IDEs allow you to configure the "Tab" key to insert spaces instead of tabs.

For VS Code: Go to Settings → Editor: Insert Spaces → Set it to true.

Example:

def greet():
    print("Hello")  # Indented with 4 spaces
  print("Hi there!")  # Indented with a tab (incorrect)

In this example, mixing spaces and tabs results in an IndentationError.

3. Check and Fix Mixed Indentation (Spaces vs. Tabs)

Mixing spaces and tabs will cause errors. Use the "Show Invisibles" feature in your editor to visualize spaces and tabs. Make sure all indentation is consistent throughout your code.

4. Follow Consistent Indentation Levels

Ensure that all statements inside the same block (loops, conditionals, functions) are indented to the same level. Inconsistent indentation will lead to an IndentationError.

Correct Example:

if True:
    print("This is correct")  # Indented with 4 spaces
    print("Inside the if block")  # Same indentation level

Incorrect Example:

if True:
    print("This is correct")
   print("This will cause an indentation error")  # Inconsistent indentation

5. Use IDE Features to Automatically Format Code

Many IDEs have auto-formatting or auto-indentation features that adjust the indentation when you write or modify code.

In VS Code: Use Shift + Alt + F to auto-format the code and fix indentation issues.

6. Indent After Control Flow Statements

When writing control flow statements (like if, for, while), make sure that the following line is indented properly.

Correct Example:

if x > 10:
    print("x is greater than 10")

Incorrect Example:


if x > 10:
print("x is greater than 10")  # This will raise an IndentationError

7. Be Careful with Nested Code Blocks

Nested code blocks require additional levels of indentation. Ensure each level is properly indented to avoid indentation errors.

Example of Nested Code:

def check_number(x):
    if x > 10:
        print("x is greater than 10")
    else:
        print("x is less than or equal to 10")

8. Use a Linter to Catch Indentation Errors

Tools like Flake8, Pylint, or Black can help catch indentation problems and enforce consistent style. Integrate a linter into your editor to get real-time feedback.

To install Flake8:

pip install flake8

To run Flake8:

flake8 your_script.py

By following these practices and utilizing your editor's features, you can easily avoid most indentation errors and improve the readability and maintainability of your Python code.

Also Read: Python Cheat Sheet: From Fundamentals to Advanced Concepts for 2025

Next, let's explore some of the benefits and challenges of using indentation in Python coding.

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Benefits and Challenges of Using Indentation in Python

Indentation is a key part of Python’s syntax, helping you organize code in a readable and structured way. It allows you to easily visualize the hierarchy of functions, loops, and conditionals, improving code clarity and reducing errors.

However, indentation can also pose challenges. Errors can be tricky to spot, especially in large codebases, and if you’re coming from a language that uses braces or other delimiters, adapting to Python’s whitespace-based structure might take some time.

Here are some benefits and challenges of using indentation error in Python:

Benefits	Challenges
Enhanced Readability: Makes the code structure clear and easy to follow.	Corrupted Indentation in Large Codebases: Hard to identify and fix small errors in large projects.
Elimination of Delimiters: No need for braces {}, leading to cleaner and more readable code.	Adjusting to Whitespace Rules: Developers from brace-based languages may find it difficult to adapt.
Consistent Structure: Ensures uniformity, making debugging easier.	Inconsistent Spaces and Tabs: Mixing spaces and tabs can lead to errors, especially with different IDE settings.
Cleaner Code Aesthetics: Python’s indentation leads to inherently simpler and visually appealing code.	Indentation Errors in Nested Code: Deeply nested code can be harder to manage, increasing the chances of errors.
IDE Support: Editors like VS Code and PyCharm help maintain proper indentation with auto-indentation and syntax highlighting.	Difficult to Spot Errors: Small indentation mistakes are hard to detect, especially in large codebases.

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Also Read: Object Oriented Programming Concept in Python

Next, let’s look at some best practices you can follow to avoid the challenges.

Best Practices to Avoid Indentation Issues in Python

While indentation errors may seem minor, they can quickly escalate, causing confusion and breaking the flow of your code. Following best practices is crucial because it ensures your code remains clean, readable, and functional. By adhering to these practices, you not only prevent frustrating errors but also create a solid foundation for future development, making collaboration with others smoother and more efficient.

Here are some of them:

1. Use a Reliable Code Editor or IDE

Choose an editor or IDE that supports Python and helps manage indentation automatically. Popular editors like Visual Studio Code, PyCharm, and Sublime Text offer features such as:

Auto-indentation
Syntax highlighting
Indentation guides

These features help prevent indentation errors and make coding smoother.

2. Configure Editor to Use Spaces Instead of Tabs

To avoid mixing spaces and tabs, configure your editor to insert spaces when you press the "Tab" key.

This ensures consistent indentation and eliminates the possibility of accidental indentation errors.

3. Use a Linter

Linters analyze your code for syntax and style issues, including indentation problems. They can catch errors before running the code, saving time and reducing errors.

Linters also help enforce PEP 8 (Python’s style guide), ensuring your code adheres to industry-standard formatting.

4. Enable "Show Invisibles" in Editors

Many modern code editors have a “Show Invisibles” feature that allows you to visualize invisible characters like spaces, tabs, and line breaks.

This makes it easy to spot mixed indentation (spaces vs. tabs) and ensures consistent formatting.

5. Learn About Python Indentation and Common Errors

Understanding Python’s indentation rules and common pitfalls can help you avoid errors from the start.

Enroll in a Python programming course to get a deeper understanding of indentation issues and how to address them.

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Next, let’s look at how upGrad can help you understand indentation errors in Python.

How can upGrad help you in Mastering Indentation in Python?

Indentation errors are one of the most common challenges when learning Python, but the good news is they’re easy to avoid with the right approach. The key to solving it is understanding Python’s strict whitespace rules and following best practices consistently.

upGrad’s comprehensive courses can help you master these skills, making your coding smoother and more efficient.These courses are ideal for developers seeking to enhance their coding skills and avoid common coding errors.

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