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 tool runs entirely in your browser. Your files are never uploaded to a server.
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.
- Press Start to begin and unlock alarm audio. You can pause, resume, reset, or add one minute while it runs.
- 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.
Is my timer information sent anywhere?
No. The countdown and alarm are handled locally with your browser clock and Web Audio API. The duration you enter is not uploaded or stored on a server.
How we compare
| Feature | Online Tool Store | timeanddate.com Timer | iPhone Clock |
|---|---|---|---|
| Custom hours, minutes, and seconds | Yes | Yes | Yes |
| Pause, resume, and reset | Yes | Yes | Yes |
| Add time while counting | + 1 minute | Edit the timer | Available |
| Multiple simultaneous timers | One timer | Yes | Yes |
| Can alert while the device sleeps | No - browser must stay active | No - browser must stay active | Yes |
| No account or app installation | Yes | Yes | Built into the phone |
timeanddate.com is useful for managing several labeled browser timers, while 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 the essential controls immediately visible.