diff --git a/package.json b/package.json
index e8d792d4a..f993136cd 100644
--- a/package.json
+++ b/package.json
@@ -22,7 +22,7 @@
     "quick-build": "tsc --pretty",
     "small-build": "node scripts/build.js",
     "lint": "tslint -c tslint.json src/*.ts src/types/*.ts src/api/*.ts src/core/*.ts src/utils/*.ts",
-    "size": "size-limit 20KB lib/mobx.js",
+    "size": "size-limit 21KB lib/mobx.js",
     "precommit": "lint-staged"
   },
   "repository": {