diff --git a/lib/size_extension.dart b/lib/size_extension.dart
index 2ae5a49..9c1cffb 100644
--- a/lib/size_extension.dart
+++ b/lib/size_extension.dart
@@ -1,6 +1,6 @@
 import 'package:flutter_screenutil/screenutil.dart';
 
-extension SizeExtension on num {
+extension SizeExtension on double {
   ///[ScreenUtil.setWidth]
   num get w => ScreenUtil().setWidth(this);