diff --git a/nodes/core/io/21-httpin.js b/nodes/core/io/21-httpin.js
index 2e2d0962e..2843121a2 100644
--- a/nodes/core/io/21-httpin.js
+++ b/nodes/core/io/21-httpin.js
@@ -124,7 +124,7 @@ module.exports = function(RED) {
                     msg.res.jsonp(statusCode,msg.payload);
                 } else {
                     if (msg.res.get('content-length') == null) {
-                        msg.res.set('content-length', Buffer.byteLength(msg.payload));
+                        msg.res.set('content-length', ""+Buffer.byteLength(msg.payload));
                     }
                     msg.res.send(statusCode,msg.payload);
                 }