diff --git a/lib/routes.js b/lib/routes.js
index 0d0cb5d0..e6654121 100644
--- a/lib/routes.js
+++ b/lib/routes.js
@@ -56,7 +56,10 @@ app.use(compression({ threshold: 500 }))
 app.use(helmet())
 app.use(nocache())
 app.use(express.json({ limit: '2mb' }))
-app.use(morgan(':method :url :status :response-time ms -- :req[content-length]/:res[content-length] b', { stream: logger.stream }))
+
+morgan.token('bytesRead', (_req, res) => res.bytesRead)
+morgan.token('bytesWritten', (_req, res) => res.bytesWritten)
+app.use(morgan(':method :url :status :response-time ms -- :bytesRead/:bytesWritten B', { stream: logger.stream }))
 
 // app /pair and /ca routes
 app.use('/', pairingRoutes)