diff --git a/docs/usage.md b/docs/usage.md
index 2d7a9ed..50c6fe0 100644
--- a/docs/usage.md
+++ b/docs/usage.md
@@ -110,10 +110,17 @@ Let's assume you have
 
 Then with
 
+Linux:
 ```shell
 VARVAMP_CONFIG=custom_config.py varvamp qpcr input_alignment.fasta my_results
 ```
 
+Windows:
+```shell
+set "VARVAMP_CONFIG=custom_config.py"
+varvamp qpcr input_alignment.fasta my_results
+```
+
 you run the command with the parameter change applied.
 
 If, as another example, you have several custom config files, each optimized for a specific use case, stored in a folder `/home/me/my varvamp configs`, you might want to run: