diff --git a/.github/CONTRIBUTING.md b/.github/CONTRIBUTING.md
index 5dfb74b51..b0f65230c 100644
--- a/.github/CONTRIBUTING.md
+++ b/.github/CONTRIBUTING.md
@@ -153,6 +153,9 @@ files directly; instead, modify the include/nlohmann sources and regenerate the
 make amalgamate
 ```
 
+Running `make amalgamate` will also apply automatic formatting to the source files using
+[`Artistic Style`](https://astyle.sourceforge.net/). This formatting may modify your source files in-place. Be certain to review and commit any changes to avoid unintended formatting diffs in commits.
+
 ## Recommended documentation
 
 - The library’s [README file](https://github.com/nlohmann/json/blob/master/README.md) is an excellent starting point to