How to comment multiple lines in Python

How do you comment out multiple lines in Python?

Short answer: Python has no block comment syntax, so you put # at the start of each line. You don't have to type them one by one: select the lines in your editor and press Ctrl + / (Cmd + / on macOS). Press it again to uncomment.

# print("Step 1")
# print("Step 2")
print("Step 3")   # only this line runs

Triple quotes (""" or ''') also hide text, but they create a string, not a comment. Use them for docstrings, not to switch off code.

Put # on each line with Ctrl + / and Python skips those lines when it runs the file.

Shortcuts to comment multiple lines in each editor

Select the lines first, then press:

All of them add # to each line. None of them insert triple quotes.

Comment multiple lines with

The # symbol turns the rest of the line into a comment. For several lines, start each one with #:

# Calculate the total price of the order.
# Prices are in dollars and already include tax.
total = 0
for price in [10, 20, 5]:
    total += price
print(total)  # 35

This is what PEP 8, the Python style guide, recommends for block comments: each line starts with # and a single space, with the same indentation as the code it describes.

You can also add a comment at the end of a line of code. Leave at least two spaces before the #:

discount = 0.1  # 10% for new customers

Triple quotes: docstrings, not comments

A string between triple quotes can span several lines, so some people use it as a multi-line comment:

"""
print("Step 1")
print("Step 2")
"""
print("Step 3")  # Step 3

It works because Python creates the string and then throws it away. But it is still code, not a comment, and that has consequences:

• It must follow the indentation of the block where it is.
• Backslashes are read as escape sequences, so a Windows path like C:\Users inside it raises a SyntaxError.
• If the code you hide already contains triple quotes, the string ends early.

Where triple quotes really belong is in docstrings: the first string inside a function, class or module, which documents it.

def total(prices):
    """Return the sum of a list of prices.
 
    prices: a list of numbers in dollars.
    """
    return sum(prices)
 
print(total.__doc__)
help(total)

Python saves the docstring in __doc__, and help() and your editor show it when you hover over the function.

# comments vs triple quotes

Switch off a large block of code

When you need to disable a long piece of code for a while, you have three options:

1. Select it and press Ctrl + /. This is the cleanest one.
2. Wrap it in if False: and indent it. Python skips the block, and your editor still checks its syntax.
3. Delete it. If you use Git, the old version stays in the history, so you don't need to keep dead code commented out.

if False:
    send_email(user)
    log_event("email sent")

Use AI to write and clean up comments

An assistant like ChatGPT, Claude or GitHub Copilot can help you write useful comments and docstrings. These three prompts are ready to copy.

1. Write a docstring

Write a docstring for this Python function following PEP 257.
Explain the parameters, the return value and any errors it can raise: [paste the function]

2. Clean up comments

Review the comments in this Python code. Remove the ones that only repeat what the code says,
and rewrite the rest so they explain why, not what: [paste the code]

3. Understand commented-out code

This Python file has blocks of code commented out with # and triple quotes: [paste the code].
Tell me which blocks are safe to delete and which ones might still be needed.

Read every suggestion before you paste it into your project.

Common problems when commenting in Python

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