Online Timer With Sound
The short answer: this is a free online countdown timer with an alarm sound — pick a duration, press Start, and it rings when time is up while the digits turn red in the final seconds. Press Fullscreen so a whole room can see it. To keep a timer with sound on top of a PowerPoint Slide Show, download SlideTimerApp, the free desktop overlay.
How the alarm works
When the countdown hits zero, the timer plays a short alarm tone and the display flashes red. You get two cues at once — one you can hear across a room and one you can see. Because web browsers only allow audio after a user action, the sound is enabled the moment you press Start; just make sure your device isn't muted.
Use it in the classroom
A timer with sound is one of the simplest classroom-management tools there is: it ends "how much longer?" and gives every activity a clear, consistent finish line. Set the minutes, press Fullscreen to fill the projector, and let students watch the countdown. See more ideas on the classroom timer page, or grab a ready 5-minute or 10-minute timer.
Use it while presenting
For talks, webinars and workshops, a visible countdown with an alarm keeps you on schedule without checking your phone. This browser timer is perfect when you're sharing a single screen — but a browser tab can't sit on top of a full-screen slideshow. For that, use the overlay app.
Why an overlay app beats a browser tab for slideshows
| What you need | This web timer | SlideTimerApp overlay |
|---|---|---|
| Alarm sound at zero | Yes | Yes |
| Big fullscreen display | Yes | Yes |
| Floats on top of PowerPoint Slide Show | No (browser tab) | Yes |
| Stays visible while you present slides | No | Yes |
| Works in Google Slides & Canva too | Tab only | Yes |
Want the alarm on top of your slides?
SlideTimerApp floats a transparent countdown with a red warning and alarm over PowerPoint, Google Slides or Canva — free for Windows.
Download SlideTimerApp free ~3 MB · Windows · works offlineMore timers
5-minute timer
Free online 5-minute countdown with sound.
Classroom timer
A big, visible countdown for lessons.
Presentation timer
Keep talks and webinars on time.
Countdown for PowerPoint
Float a countdown over your Slide Show.
Frequently asked questions
Does this online timer have a sound?
Yes. It plays an alarm tone when the countdown reaches zero, and the digits turn red in the final seconds, so you get both an audible and a visual cue. Make sure your device isn't muted so the alarm can be heard.
Can I use a timer with sound in the classroom?
Yes. Set the minutes, press Fullscreen so the whole class can read the countdown on the projector, and the alarm signals when an activity is over. It's free, needs no sign-up, and collects no student data.
How do I turn the alarm sound on or off?
The alarm plays automatically at zero. To silence it, lower or mute your device or browser-tab volume. The first sound only works after you press Start, because browsers require a user action before playing audio.
How do I keep a timer with sound on top of PowerPoint?
A browser tab can't stay on top of a full-screen Slide Show. Download SlideTimerApp, a free Windows overlay that floats the countdown over PowerPoint, Google Slides or Canva and plays an alarm at zero, so the timer stays visible while you present.