How to Fix IndentationError in Python for Beginners

Python uses indentation (spaces or tabs at the beginning of a line) to define blocks of code. Unlike many other programming languages that use curly braces or keywords, Python’s structure relies on proper indentation. This makes the code easier to read but also means that even small mistakes in indenting can cause errors.

IndentationError happens when Python finds inconsistent or unexpected indentation. This means it’s expecting a certain level of indentation but finds something else instead. Common causes include mixing spaces and tabs, missing indentation after a colon (:), or incorrect alignment of code blocks.

def greet():
print("Hello, world!")  # This line should be indented

# Corrected version:

def greet():
    print("Hello, world!")

To fix an IndentationError, you need to make sure that all lines inside a block have the same level of indentation. Use either spaces or tabs consistently—Python’s official style guide recommends using 4 spaces per indentation level. Most code editors allow you to set this preference. Check your code blocks carefully after colons and before special statements to ensure proper indentation.