diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index 7378c8740..54d012070 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -11,7 +11,7 @@ If you want to implement something big:
 
 ## Python
 
-Paperless supports python 3.8 and 3.9.
+Paperless supports python 3.8 and 3.9. We format Python code with [Black](https://github.com/psf/black).
 
 ## Branches
 
@@ -23,7 +23,7 @@ Paperless supports python 3.8 and 3.9.
 
 ## Testing:
 
-Please test your code! I know it's a hassle, but it makes sure that your code works now and will allow us to detect regressions easily.
+Please format and test your code! I know it's a hassle, but it makes sure that your code works now and will allow us to detect regressions easily.
 
 To test your code, execute `pytest` in the src/ directory. This also generates a html coverage report, which you can use to see if you missed anything important during testing.
 
diff --git a/docs/extending.rst b/docs/extending.rst
index f51ecc3a7..6b94b4c26 100644
--- a/docs/extending.rst
+++ b/docs/extending.rst
@@ -107,6 +107,7 @@ Testing and code style:
 *   Run ``pytest`` in the src/ directory to execute all tests. This also generates a HTML coverage
     report. When runnings test, paperless.conf is loaded as well. However: the tests rely on the default
     configuration. This is not ideal. But for now, make sure no settings except for DEBUG are overridden when testing.
+*   Run ``black`` to format your code.
 *   Run ``pycodestyle`` to test your code for issues with the configured code style settings.
 
     .. note::