diff --git a/package.json b/package.json
index 5cf5c80..ab4f6f4 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,7 @@
 {
   "private": true,
   "devDependencies": {
+    "gzip-size-cli": "^2.1.0",
     "karma": "1.7.1",
     "karma-chrome-launcher": "2.2.0",
     "karma-cljs-test": "0.1.0",
diff --git a/test-environments/browser-umd-prod/test.sh b/test-environments/browser-umd-prod/test.sh
index bb788bf..c015e8e 100755
--- a/test-environments/browser-umd-prod/test.sh
+++ b/test-environments/browser-umd-prod/test.sh
@@ -2,3 +2,4 @@
 set -ex
 lein do clean, doo chrome-headless prod-test once
 test -f target/cljsbuild/prod-test/main.js
+../../node_modules/.bin/gzip-size target/cljsbuild/prod-test/main.js