Online Tool Store
Countdown Timer
Set a free countdown timer for hours, minutes, or seconds, then pause, resume, or add time before the browser alarm sounds. Runs entirely on your device.
This works right here on your device — nothing gets sent out.
00:05:00
Ready for a 5 minute countdown
Quick timers
A 5 minute example is ready - set another duration or press Start.
How the countdown timer works
- Enter a duration in hours, minutes, and seconds, or choose a quick preset from 1 minute to 1 hour.
- Pick an alarm sound and volume, then press Start to begin and unlock alarm audio. You can pause, resume, reset, or add one minute while it runs.
- Use Fullscreen for a large, distraction-free display. A running countdown carries on if you reload the page.
- At zero, the timer sounds an alarm, flashes the tab title, and shows Repeat and Dismiss controls.
How the time stays accurate
When the timer starts, it records an exact finish time. Every display update subtracts the current time from that finish time instead of simply removing one second from a counter.
time remaining = finish time - current time
The ready-made example is five minutes, so pressing Start sets the finish time to exactly five minutes from that moment. This deadline method prevents small browser scheduling delays from accumulating into a slow timer.
FAQ
Will the timer ring if I close the tab or my device goes to sleep?
No. This is a browser timer, so the tab must stay open and your device must remain awake. If the browser suspends the page, the timer catches up from the real clock when the page runs again, but the alarm cannot sound while the device is asleep.
Why do I need to press Start before the alarm can sound?
Browsers normally block pages from playing audio without a user action. Pressing Start unlocks the browser-generated alarm sound so it can play when the countdown reaches zero.
Can I pause the timer or add more time?
Yes. Pause freezes the remaining duration, Resume continues from it, and the + 1 minute button extends either a running or paused timer without starting over.
What is the longest countdown I can set?
The duration fields accept up to 999 hours, 59 minutes, and 59 seconds. Hours can be greater than 24 because this is a duration rather than a time of day.
Does the timer keep running if I reload the page?
Yes. While a countdown is running, its exact finish time is saved in your browser, so reloading or reopening the page picks it up with the correct time left. If the time ran out while the page was closed, it shows that the countdown has finished instead. A paused timer is not saved. Because browsers block sound until you interact with a page, click anywhere after reloading to re-enable the alarm.
Can I change the alarm sound and volume?
Yes. Choose Beep, Chime, or Digital and set the volume with the slider. Changing either plays a preview, and Test sound plays it again. Your choices are remembered in this browser.
How do I make the timer full screen?
Press Fullscreen on the timer display to show only the countdown, large enough to read from across a room. Press Exit fullscreen or the Esc key to return.
Is my timer information sent anywhere?
No. The countdown and alarm are handled locally with your browser clock and Web Audio API. Nothing is uploaded. Only your alarm settings and any running countdown's finish time are kept in your browser's local storage on this device.
How we compare
| Feature | Online Tool Store | CoolTimer | vClock | TickCounter |
|---|---|---|---|---|
| Fullscreen display | Yes | Yes | Yes | Not listed |
| Choice of alarm sounds | Beep, Chime, Digital | Variety of sounds | Preset sounds | Alarm sound |
| Volume control and sound preview | Yes | Not listed | Yes | Not listed |
| Quick presets | 1 min to 1 hour | Not listed | 1 minute to 8 hours | URL presets |
| Countdown survives closing or reloading the page | Yes, while running | Yes | Not listed | Not listed |
| Pause, resume and add a minute | Yes | Pause and resume | Not listed | Start, stop and reset |
CoolTimer runs several labeled timers at once, and vClock offers date-based countdowns, longer presets, shareable links and an embeddable widget, none of which this tool does. iPhone Clock is better when a timer must survive device sleep. Choose Online Tool Store's Countdown Timer for a focused, no-install countdown with a fullscreen view, your choice of alarm, and no account.