Auto-Format Python Code with the Ruff VS Code Extension

Writing clean, consistently formatted code is important — not just for looks, but because messy code is harder to debug and share. Ruff is a modern Python tool that handles formatting, linting, and import sorting automatically, so you never have to think about style rules again.

What is Ruff?

Ruff is a modern Python tool that is incredibly fast and combines multiple tools in one:

Linting — finding issues and potential errors in your code
Formatting — automatically fixing code style
Import sorting — organizing imports cleanly

It is beginner-friendly with clear error messages and works seamlessly with VS Code.

A linter checks your code for style issues and potential errors. A formatter automatically fixes those issues for you. Ruff does both.

Install Ruff in VS Code

Open VS Code
Press Ctrl + Shift + X (Windows/Linux) or Cmd + Shift + X (macOS) to open Extensions
Search for Ruff
Install the official Ruff extension by Astral

The Ruff extension replaces older tools like Pylint, Black, and isort. You only need this one extension for all three jobs.

Enable format on save

Let VS Code automatically format your code every time you press Save:

Open Settings with Ctrl + , (Windows/Linux) or Cmd + , (macOS)
Search for format on save
Check the box for Editor: Format On Save
Search for default formatter
Set Python → Formatting: Provider to Ruff

See Ruff in action

Here is messy code before saving:

import os
def   calculate_total(items):
    total=0
    for item in items:
        total+=item['price']*item['quantity']
    return total

shopping_cart=[{'name':'apple','price':0.5,'quantity':6},{'name':'banana','price':0.3,'quantity':8}]
print(calculate_total(shopping_cart))

After saving with Ruff enabled, the file is automatically reformatted to:

import os


def calculate_total(items):
    total = 0
    for item in items:
        total += item["price"] * item["quantity"]
    return total


shopping_cart = [
    {"name": "apple", "price": 0.5, "quantity": 6},
    {"name": "banana", "price": 0.3, "quantity": 8},
]
print(calculate_total(shopping_cart))

Ruff automatically:

Separated imports from the rest of the code
Added proper spacing around operators
Fixed indentation
Made quote style consistent (double quotes)
Reformatted the long list for readability

If formatting does not trigger on save, right-click inside your Python file and select Format Document. This runs Ruff manually and also confirms the extension is working.

Common formatting rules

Ruff follows Python’s official style guide (PEP 8) automatically:

4 spaces for indentation (never tabs)
Spaces around operators (x = 1, not x=1)
Two blank lines between top-level functions
Maximum line length of 88 characters

You do not need to memorize any of these — Ruff handles them every time you save.

Understanding linting errors

Ruff will underline code issues in your editor. For example:

# Unused imports — Ruff warns you
import os
import sys

# Only sys is used below
print(sys.version)

Hover over any underlined code to see:

What the issue is
Why it matters
How to fix it

Do not ignore linting warnings. They help you write better code and catch real bugs before they cause problems at runtime.

What’s next?

With Ruff set up, your code will always look professional and follow best practices automatically. Every file you save is clean, readable, and consistent.

Welcome

Setup

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Auto-Format Python Code with the Ruff VS Code Extension

What is Ruff?

Install Ruff in VS Code

Enable format on save

See Ruff in action

Common formatting rules

Understanding linting errors

What’s next?

​What is Ruff?

​Install Ruff in VS Code

​Enable format on save

​See Ruff in action

​Common formatting rules

​Understanding linting errors

​What’s next?

What is Ruff?

Install Ruff in VS Code

Enable format on save

See Ruff in action

Common formatting rules

Understanding linting errors

What’s next?