diff --git a/luhn-algorithm/index.html b/luhn-algorithm/index.html
index 38014e1..a26d68e 100644
--- a/luhn-algorithm/index.html
+++ b/luhn-algorithm/index.html
@@ -43,6 +43,15 @@
         <script src="/assets/global.js"></script>
         <link href="style.css" rel="stylesheet">
         <link href="/assets/global.css" rel="stylesheet">
+
+        <!-- Global site tag (gtag.js) - Google Analytics -->
+        <script async src="https://www.googletagmanager.com/gtag/js?id=UA-124505000-1"></script>
+        <script>
+            window.dataLayer = window.dataLayer || [];
+            function gtag(){dataLayer.push(arguments);}
+            gtag('js', new Date());
+            gtag('config', 'UA-124505000-1');
+        </script>
     </head>
     <body>
         <!-- cookie notice is included via jQuery -->
