diff --git a/index.php b/index.php
index 40eea8f..3d3293f 100644
--- a/index.php
+++ b/index.php
@@ -9,9 +9,9 @@
     <?php echo '<p>Hello World</p>'; ?>
         <h1>Welcome to my page.</h1>
         <ul>
-            <li><a href="https://lukerufkahr.com/notes/physics.html">Physics</a></li>
-            <li><a href="https://lukerufkahr.com/notes/circuits.html">Circuits</a></li>
-            <li><a href="https://lukerufkahr.com/notes/cpp.html">C++</a></li>
+            <li><a href="https://lukerufkahr.com/notes/physics.php">Physics</a></li>
+            <li><a href="https://lukerufkahr.com/notes/circuits.php">Circuits</a></li>
+            <li><a href="https://lukerufkahr.com/notes/cpp.php">C++</a></li>
         </ul>
     </main>
 </body>