diff --git a/Sprint-3/alarmclock/alarmclock.js b/Sprint-3/alarmclock/alarmclock.js
index 6ca81cd3b..9f8f1606c 100644
--- a/Sprint-3/alarmclock/alarmclock.js
+++ b/Sprint-3/alarmclock/alarmclock.js
@@ -1,4 +1,55 @@
-function setAlarm() {}
+const heading = document.querySelector("#timeRemaining");
+const input = document.querySelector("#alarmSet");
+const startBtn = document.querySelector("#set");
+const stopBtn = document.querySelector("#stop");
+
+let timer = null;
+
+function renderTime(totalSeconds) {
+  const minutes = Math.floor(totalSeconds / 60);
+  const seconds = totalSeconds % 60;
+  const mm = String(minutes).padStart(2, "0");
+  const ss = String(seconds).padStart(2, "0");
+  heading.innerText = `Time Remaining: ${mm}:${ss}`;
+}
+
+function setAlarm() {
+  const rawValue = input.value.trim();
+  if (rawValue === "") {
+    return;
+  }
+
+  let totalSeconds = Number(rawValue);
+  if (Number.isNaN(totalSeconds) || totalSeconds < 0) {
+    return;
+  }
+
+  if (timer !== null) {
+    clearInterval(timer);
+  }
+
+  renderTime(totalSeconds);
+
+  if (totalSeconds === 0) {
+    playAlarm();
+    timer = null;
+    input.value = "";
+    return;
+  }
+
+  timer = setInterval(() => {
+    totalSeconds--;
+    renderTime(totalSeconds);
+
+    if (totalSeconds === 0) {
+      clearInterval(timer);
+      timer = null;
+      playAlarm();
+    }
+  }, 1000);
+
+  input.value = "";
+}
 
 // DO NOT EDIT BELOW HERE
 
diff --git a/Sprint-3/alarmclock/index.html b/Sprint-3/alarmclock/index.html
index 48e2e80d9..36715d7d9 100644
--- a/Sprint-3/alarmclock/index.html
+++ b/Sprint-3/alarmclock/index.html
@@ -1,20 +1,23 @@
 <!DOCTYPE html>
 <html lang="en">
-  <head>
-    <meta charset="utf-8" />
-    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
-    <link rel="stylesheet" href="style.css" />
-    <title>Title here</title>
-  </head>
-  <body>
-    <div class="centre">
-      <h1 id="timeRemaining">Time Remaining: 00:00</h1>
-      <label for="alarmSet">Set time to:</label>
-      <input id="alarmSet" type="number" />
 
-      <button id="set" type="button">Set Alarm</button>
-      <button id="stop" type="button">Stop Alarm</button>
-    </div>
-    <script src="alarmclock.js"></script>
-  </body>
-</html>
+<head>
+  <meta charset="utf-8" />
+  <meta name="viewport" content="width=device-width, initial-scale=1.0" />
+  <link rel="stylesheet" href="style.css" />
+  <title>Alarm clock app</title>
+</head>
+
+<body>
+  <div class="centre">
+    <h1 id="timeRemaining">Time Remaining: 00:00</h1>
+    <label for="alarmSet">Set time to:</label>
+    <input id="alarmSet" type="number" />
+
+    <button id="set" type="button">Set Alarm</button>
+    <button id="stop" type="button">Stop Alarm</button>
+  </div>
+  <script src="alarmclock.js"></script>
+</body>
+
+</html>
\ No newline at end of file
