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20 Second Timer — Online Countdown

Free online 20 second timer — a big, clear countdown that rings when time is up, with alarm sound, notification and fullscreen. Set it and go; no download needed.

00:00
Set your own: h m s
Timer options
When it ends
Sound
Label Optional name — it appears above the timer and in the alert when time is up (e.g. "Tea — time is up!").

What is the 20 Second Timer?

The 20 second timer is a free online countdown timer preset to 20 seconds. Just press Start and it counts down to zero, then plays an alarm and shows a notification — even if you have switched to another browser tab. There is nothing to install. It is handy for cooking, workouts, study breaks, games and any task you want to keep to time.

How to set a 20 second timer

  1. This page is already set to 20 seconds — or change it in the "Set your own" boxes and press Set.
  2. Press Start to begin the countdown. Use Pause to hold it, or Reset to start over.
  3. Add time on the fly with +1 min / +5 min, or trim it with −1 min.
  4. When it reaches zero you will hear the alarm and get a notification. Choose the sound, repeat and what happens on zero under Timer options.

Timer features

  • Alarm sounds — beep, chime, bell or digital, with an optional repeat until you stop it.
  • Desktop & phone notification the moment time is up.
  • Runs in the background — the remaining time shows in the browser tab while you work elsewhere.
  • Fullscreen mode for a big, across-the-room display — great for classrooms, workouts and streams.
  • On-zero options — stop, auto-restart (loop), or roll into a stopwatch.
  • Free, no download, no sign-up — it works entirely in your browser.

More timers

Set a timer for 1 minute, 2 minutes, 3 minutes, 5 minutes, 10 minutes, 15 minutes, 20 minutes, 25 minutes, 30 minutes, 45 minutes or 60 minutes — or use the online stopwatch and the 1 hour timer.

Frequently asked questions

How do I set a 20 second timer?
Just press Start — this page is preset to 20 seconds. You can also change the time in the "Set your own" boxes.

Does the 20 second timer have an alarm sound?
Yes — it rings an alarm when the countdown reaches zero. You can choose the sound (beep, chime, bell or digital), turn on repeat, or mute it.

Does the timer work in the background or when I switch tabs?
Yes. It keeps counting accurately in the background, shows the time left in the browser tab title, and still alarms and notifies you when it finishes.

Do I need to download an app?
No — it is a free online timer that runs in any browser, with no download, install or sign-up.

Can I set a different time?
Yes — use the "Set your own" hours, minutes and seconds boxes, or pick another preset. Setting a time also opens its own shareable page.