diff --git a/lib/jquery.sizes.js b/lib/jquery.sizes.js
index 5aaa695..421e7bd 100755
--- a/lib/jquery.sizes.js
+++ b/lib/jquery.sizes.js
@@ -6,7 +6,36 @@
  * All rights reserved.
  */
 /*global jQuery*/
-(function ($) {
+
+// https://github.com/umdjs/umd/blob/master/templates/jqueryPlugin.js
+// Uses CommonJS, AMD or browser globals to create a jQuery plugin.
+(function (factory) {
+  if (typeof define === 'function' && define.amd) {
+    // AMD. Register as an anonymous module.
+    define(['jquery'], factory);
+  } else if (typeof module === 'object' && module.exports) {
+    // Node/CommonJS
+    module.exports = function( root, jQuery ) {
+      if ( jQuery === undefined ) {
+        // require('jQuery') returns a factory that requires window to
+        // build a jQuery instance, we normalize how we use modules
+        // that require this pattern but the window provided is a noop
+        // if it's defined (how jquery works)
+        if ( typeof window !== 'undefined' ) {
+          jQuery = require('jquery');
+        }
+        else {
+          jQuery = require('jquery')(root);
+        }
+      }
+      factory(jQuery);
+      return jQuery;
+    };
+  } else {
+    // Browser globals
+    factory(jQuery);
+  }
+}(function ($) {
 	'use strict';
 	var num = function (value) {
 			return parseInt(value, 10) || 0;
@@ -73,4 +102,4 @@
 			return this;
 		};
 	});
-}(jQuery));
+}));
diff --git a/package.json b/package.json
index 8fbb07c..a883aaf 100644
--- a/package.json
+++ b/package.json
@@ -2,6 +2,7 @@
   "name": "jquery-sizes",
   "version": "0.33.0",
   "description": "jQuery extension plugin for CSS properties",
+  "main": "lib/jquery.sizes.js",
   "keywords": [
     "jQuery sizes jsizes"
   ],
@@ -34,4 +35,4 @@
     "env": "env",
     "echo": "echo \"\""
   }
-}
\ No newline at end of file
+}