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Online timer

Set a duration and start the timer, it beeps when time is up.

How Online timer works

Online Timer counts down from any duration you set and plays a sound alert when it reaches zero. You enter the hours, minutes and seconds directly, click start, and the browser counts down using a JavaScript interval. When the timer expires, a brief audio tone plays through your device's speakers. The entire thing runs locally in the browser tab; no account, no network request and no server is involved.

The sound alert is generated using the Web Audio API, which synthesises a short beep without loading any external audio file. This means the alert works offline and does not depend on a CDN or remote asset. You can pause and resume at any point, and reset to re-enter a new duration. The timer is accurate to within the precision of the browser's interval timing, which is typically within one second over short durations.

Written by Bastien Sulyan

How to use Online timer, step by step

  1. Enter the desired hours, minutes and seconds in the fields provided.
  2. Click start to begin the countdown.
  3. Click pause to freeze the remaining time, then click resume to continue.
  4. Click reset to return to your originally entered duration and start again.
  5. Listen for the audio tone that plays when the timer reaches zero.

Common use cases

  • A chef sets a 12-minute timer to track how long pasta has been boiling without needing a physical kitchen timer.
  • A teacher uses the timer on a classroom screen to impose a strict time limit on a quiz or group activity.
  • A developer times how long a local build takes by starting the timer and listening for the alert when returning from another task.
  • A presenter uses a timer to keep talk segments within their allotted slot during rehearsal.

Frequently asked questions

What sound does the timer play when it expires?

The alert is a short synthesised beep produced by the Web Audio API directly inside the browser. No audio file is downloaded and no external service is contacted. The tone plays through whatever audio output your device currently has set.

Does the timer keep running if I switch to another browser tab?

Yes. The countdown is driven by a JavaScript interval that continues running even when the tab is not in focus. Most browsers throttle timers in background tabs, so for very short intervals accuracy may decrease slightly, but for durations measured in minutes the timer remains accurate.

Can I set a timer for more than 24 hours?

Yes. Enter the total hours in the hours field; values above 23 are accepted. The timer counts down continuously until zero regardless of how many hours are entered.

Does the timer send anything to a server when it starts or finishes?

No. The countdown logic runs in JavaScript inside your browser tab. The timer start, pause, resume and expiry events are all local. Nothing about your use of the timer is transmitted anywhere.

Will the alarm play if my device is on silent?

The Web Audio API is subject to your browser's audio permissions and your device's volume settings. If your device or browser is muted, the alert will not be audible. Watch the visual indicator on screen if you have audio muted.