openpyxl - A Python library to read/write Excel 2010 xlsx/xlsm files


Eric Gazoni, Charlie Clark

Source code:



May 29, 2024





coverage status


openpyxl is a Python library to read/write Excel 2010 xlsx/xlsm/xltx/xltm files.

It was born from lack of existing library to read/write natively from Python the Office Open XML format.

All kudos to the PHPExcel team as openpyxl was initially based on PHPExcel.


By default openpyxl does not guard against quadratic blowup or billion laughs xml attacks. To guard against these attacks install defusedxml.

Mailing List

The user list can be found on

Sample code:

from openpyxl import Workbook
wb = Workbook()

# grab the active worksheet
ws =

# Data can be assigned directly to cells
ws['A1'] = 42

# Rows can also be appended
ws.append([1, 2, 3])

# Python types will automatically be converted
import datetime
ws['A2'] =

# Save the file"sample.xlsx")


The documentation is at:

  • installation methods

  • code examples

  • instructions for contributing

Release notes:


This is an open source project, maintained by volunteers in their spare time. This may well mean that particular features or functions that you would like are missing. But things don’t have to stay that way. You can contribute the project Development yourself or contract a developer for particular features.

Professional support for openpyxl is available from Clark Consulting & Research and Adimian. Donations to the project to support further development and maintenance are welcome.

Bug reports and feature requests should be submitted using the issue tracker. Please provide a full traceback of any error you see and if possible a sample file. If for reasons of confidentiality you are unable to make a file publicly available then contact of one the developers.

The repository is being provided by Octobus and Clever Cloud.

How to Contribute

Any help will be greatly appreciated, just follow those steps:

1. Please join the group and create a branch ( and follow the Merge Request Start Guide. for each independent feature, don’t try to fix all problems at the same time, it’s easier for those who will review and merge your changes ;-)

2. Hack hack hack

3. Don’t forget to add unit tests for your changes! (YES, even if it’s a one-liner, changes without tests will not be accepted.) There are plenty of examples in the source if you lack know-how or inspiration.

4. If you added a whole new feature, or just improved something, you can be proud of it, so add yourself to the AUTHORS file :-)

5. Let people know about the shiny thing you just implemented, update the docs!

6. When it’s done, just issue a pull request (click on the large “pull request” button on your repository) and wait for your code to be reviewed, and, if you followed all theses steps, merged into the main repository.

For further information see Development

Other ways to help

There are several ways to contribute, even if you can’t code (or can’t code well):

  • triaging bugs on the bug tracker: closing bugs that have already been closed, are not relevant, cannot be reproduced, …

  • updating documentation in virtually every area: many large features have been added (mainly about charts and images at the moment) but without any documentation, it’s pretty hard to do anything with it

  • proposing compatibility fixes for different versions of Python: we support 3.6, 3.7, 3.8 and 3.9.

API Documentation

Key Classes

Indices and tables