diff --git a/index.html b/index.html
index 919d046..2abdc14 100644
--- a/index.html
+++ b/index.html
@@ -1,6 +1,14 @@
 <!DOCTYPE html>
 <html>
   <head>
+    <!-- Google tag (gtag.js) -->
+    <script async src="https://www.googletagmanager.com/gtag/js?id=G-2LJSDH860E"></script>
+    <script>
+      window.dataLayer = window.dataLayer || [];
+      function gtag(){dataLayer.push(arguments);}
+      gtag('js', new Date());  
+      gtag('config', 'G-2LJSDH860E');
+    </script>
     <meta charset="UTF-8">
     <title>sexp-trees</title>
     <link rel="stylesheet" type="text/css" href="styles/bootstrap.min.css">
