diff --git a/docs/install.rst b/docs/install.rst
index f293e7a..26e5df4 100644
--- a/docs/install.rst
+++ b/docs/install.rst
@@ -153,6 +153,8 @@ These nodes will be used in Node-RED:
     npm install node-red-contrib-python3-function
     npm install node-red-contrib-camerapi
     npm install node-red-node-mysql
+    npm install node-red-contrib-calc
+
 
 
 Stream the picamera