Set hours, minutes, and seconds, press Start, and get an alarm, a flashing tab, and a notification when time is up.
This online timer counts down from any duration in hours, minutes, and seconds and sounds an alarm when it reaches zero. It is built for cooking, workouts, studying, presentations, classroom activities, and anything else that needs a reliable countdown on a laptop or phone. Preset chips set common durations in one tap, the space bar starts and pauses, and a full-screen mode turns the display into a large wall clock that is readable from across a room. The duration is stored in the page address, so you can bookmark or share a link that opens with the same time already set.
When you press Start, the timer records a target end time (the current clock time plus the remaining seconds) and, several times a second, recomputes the remaining time as the difference between that target and the current clock. Because it measures against the system clock rather than counting ticks, it stays accurate even if the browser throttles timers in a background tab. When the remaining time reaches zero it plays three short tones through the Web Audio API, alternates the page title so the tab flashes, and sends a browser notification if you have allowed notifications. The duration is saved in the URL hash as a number of seconds (for example #t=300).
Yes. The countdown is computed from a fixed end time compared against the system clock, so it does not drift when a browser slows down timers in a background tab. The alarm sound and the flashing tab title will fire when you come back, and a desktop notification appears at the moment it finishes if you allowed notifications.
Browsers only allow sound after you interact with the page, so the alarm requires that you started the timer with a click or key press on this page. Check that the Sound option is ticked, that the device is not muted, and that the tab is not muted in the browser. Some mobile browsers also silence audio when the screen is locked.
Type the number of hours in the Hours field, or type minutes larger than 59 (for example 90) and the timer will convert them. The display switches to an hours:minutes:seconds format once the remaining time is 60 minutes or more, and the maximum is 99 hours.
Yes. The duration is stored in the page address as seconds, such as #t=1500 for 25 minutes. Use the Copy link button and send or bookmark that address; opening it sets the same duration, ready to start. The running state itself is not shared, only the duration.
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