Indentation Error in Python: Causes, How to Solve, Benefits

As a Python programmer, it can be frustrating to have your project come to a standstill due to an error in your code. One common issue that programmers often have to deal with is an indentation error. 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 of 2024, nearly 51% of developers use Python for their projects. Therefore, you should learn how to resolve Python indentation errors anytime they occur.  In this blog, you'll learn about the causes, examples, and challenges related to indentation errors in Python.

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What is an Indentation Error in Python? 

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 Blocks of Code in Python

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.

Example of a Block in Python: In this

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

Examples of Indentation Errors

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

Error Message: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. 

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

Common Python Indentation Errors 

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. 

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

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 example in Python to develop a clearer understanding. 

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

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

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.

Recommendations for Maintaining Consistent Indentation

• Choose a Standard Indentation Style (Spaces or Tabs): Decide whether to use spaces or tabs for indentation and stick to one choice throughout your code. This is the best method to avoid indentation error in Python.
• Example (using 4 spaces for indentation):

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

Configure Your Editor to Use Spaces Instead of Tabs Most modern text editors and IDEs allow you to configure whether the "Tab" key inserts spaces or tabs. Set your editor to use 4 spaces for each tab press.

• Example:

In VS Code, go to Settings → Editor: Insert Spaces and set it to true.

• Check and Fix Mixed Indentation (Spaces vs. Tabs) Mixing spaces and tabs in the same file will result in an IndentationError. Use the "Show Invisibles" feature in your editor to visualize spaces and tabs, as this helps identify any inconsistencies.

Example:

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

In this indentation example in Python, the second print statement will throw an indentation error in Python because the indentation is inconsistent.

Tips for Beginners Using Indentation in Python

• Follow Consistent Indentation Levels: All statements inside the same block (loops, conditionals, functions) must be indented to the same level. Inconsistent indentation will lead to indentation error in Python.

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

Use IDE Features to Automatically Format Code Many IDEs have auto-formatting or auto-indentation features that can automatically adjust the indentation when you write or modify code. Make sure your editor has this feature enabled.

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

Indent After Control Flow Statements (Loops, Conditionals, etc.) Whenever you write a control flow statement (like if, for, or while), make sure that the following line is indented.
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

Be Careful with Nested Code Blocks Indentation becomes especially important with nested code blocks. Always ensure that each level of nesting is properly indented to steer avoid indentation error in Python. 

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")

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..

Example:

• Install Flake8:

pip install flake8

• Run Flake8 to check for style issues:

flake8 your_script.py

By adhering to these guidelines and utilizing your editor's features, you can prevent most indentation errors and make your Python code more readable and maintainable.

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

Also Read: Python Tutorial: Setting Up, Tools, Features, Applications, Benefits, Comparison

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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.

In this section, you’ll learn about the benefits and potential pitfalls of Python’s indentation system, along with tips for tackling common issues.

Also Read: Object Oriented Programming Concept in Python

Benefits of Using Indentation in Python

Proper indentation in Python offers several advantages, contributing to cleaner, more readable, and maintainable code. Here are some key benefits:

• Enhanced Readability and Understanding of Code Hierarchy

Indentation clearly defines the structure of the code, making it easier to understand the relationships between different blocks, such as loops, conditionals, and functions. 

• Elimination of the Need for Delimiters Like Braces

Unlike other programming languages, which use braces {} to define code blocks, Python relies on indentation. This feature eliminates visual clutter and simplifies the code by removing unnecessary characters, leading to cleaner, more elegant syntax.

• Consistent Structure for Easier Debugging

Python's indentation rules enforce a uniform structure throughout the code, which makes it easier to debug. The absence of misplaced braces or forgotten block delimiters ensures that any issues related to block structure are immediately noticeable.

• Cleaner and More Beautiful Code

Python's reliance on indentation for code hierarchy results in code that is inherently more readable and aesthetically pleasing. The uniformity of indentation makes Python code stand out for its simplicity and elegance.

• Role of IDEs and Auto-Formatters in Maintaining Proper Indentation

Integrated Development Environments (IDEs) and code editors (such as Visual Studio Code, PyCharm, and Sublime Text) play a crucial role in maintaining proper indentation. These tools often provide features like auto-indentation, syntax highlighting, and visual guides to help developers follow the correct indentation standards. 

By adhering to proper indentation practices, Python developers can ensure their code is both functional and aesthetically pleasing, making it easier to maintain, debug, and share with others.

Challenges of Using Indentation in Python

Python's use of indentation for defining code blocks also presents several challenges, especially for developers who are new to it or working with large codebases. Here are some common issues:

• Difficulty in Fixing Corrupted Indentation in Large Codebases

In large projects with complex, deeply nested code, identifying and fixing indentation errors can be difficult. A small mistake, such as an extra space or a misaligned tab, can cause an indentation error in Python.

• Adjusting to Python's Whitespace Rules for Developers Familiar with Other Languages

Developers transitioning from languages that use braces may find it difficult to adjust to Python's strict indentation rules, which can lead to indentation errors. Python uses only whitespace, making it less intuitive for those accustomed to explicit block markers.

• Inconsistency Between Spaces and Tabs

Mixing spaces and tabs in the same code file is one of the most common sources of indentation errors. It can be particularly challenging in larger teams where different developers may have different IDE settings, leading to hard-to-detect issues.

Also Read: Top 7 Python Features Every Python Developer Should Know

Best Practices to Avoid Indentation Issues in Python 

Let's now have a look at some practical tips and best practices to help you overcome these challenges, so that you can keep your Python code error-free and easy to maintain. 

• 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 provide features like auto-indentation, syntax highlighting, and indentation guides to prevent indentation error in Python. 

• Configure Editor to Use Spaces Instead of Tabs

To prevent the mixing of spaces and tabs, configure your editor to insert spaces when the "Tab" key is pressed. 

• Use a Linter

A linter is a tool that analyzes your code for syntax and style issues, including indentation problems. Linters can help catch indentation errors before running the code, saving time and reducing the chances of errors. These tools can also enforce Python's PEP 8 style guide, ensuring that the code adheres to industry-standard formatting.

• Enable "Show Invisibles" in Editors

Many code editors allow you to visualize invisible characters such as spaces, tabs, and line breaks. Enabling this feature helps to identify where spaces or tabs are being used, making it easier to spot mixed indentation.

By using the right tools and practices, developers can mitigate the challenges associated with Python's indentation rules and maintain cleaner, more reliable code.

Learning about Python coding and possible indentation errors is a great way to boost your future career prospects. Enrolling for a Python programming course will help you to learn about indentation issues and how to avoid them. 

Also Read: Recurrent Neural Network in Python: Ultimate Guide for Beginners

How can upGrad help you in Mastering Indentation in Python? 

With Python being one of the most widely used programming languages, there is always a demand for professionals who are skilled at working with it. A comprehensive Python course that offers complete guidance on avoiding indentation errors can certainly help you to improve your career prospects. 

upGrad offers some of the most comprehensive Python programming courses for developers. By signing up for these courses, you can cultivate an in-depth understanding of writing Python codes while avoiding indentation errors. 

Here are some of the top courses that can help you master Python:

• Learn Basic Python Programming
• Programming with Python: Introduction for Beginners

With upGrad, you get to benefit from global standard education facilities right here in India. upGrad also offers free Python courses with certificates, which can be excellent for you if you are interested in data science and machine learning. 

By signing up for upGrad Python courses, you can benefit from the knowledge and expertise of some of the finest teachers in the country. These educators are familiar with the diverse challenges Python programmers face, and they can guide you to avoid them every time.

So, talk to an upGrad counselor today to learn about how you can benefit from a Python course.

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References:  
https://www.statista.com/statistics/793628/worldwide-developer-survey-most-used-languages/