Countdown Timer guide
Set a countdown in hours, minutes, and seconds, or tap a preset like 5, 25, or 60 minutes. Pause, resume, and reset at any time; the timer beeps and shows an alert in the browser tab title when it reaches zero.
Why many browser timers drift, and why this one doesn't
The naive way to build a countdown is to subtract one second every time a one-second interval fires. It looks fine for a minute and then quietly goes wrong. Browsers treat setInterval as a request, not a promise: a busy page can delay ticks, and background tabs are throttled to save battery, so ticks may arrive once per second at best and much less often when a tab has been hidden for a while. Each late tick adds error, and a 25-minute timer can end up running long.
This timer records the exact end time when you press Start and, several times a second, computes the remaining time as end time minus the current clock. Late ticks don't matter because each update reads the real time. Switch tabs, come back ten minutes later, and the display is exactly right. Pause stores the remaining milliseconds; Resume sets a fresh end time from them.
Features at a glance
Set hours, minutes, and seconds, or tap a preset from 1 to 60 minutes. The display shows minutes and seconds, switching to hours:minutes:seconds for anything an hour or longer. While the timer runs, the remaining time also appears in the browser tab title, so you can keep an eye on it from another tab.
At zero you get three short beeps, generated with the Web Audio API so there is no sound file to download, plus a 'Time's up' message on the page and in the tab title. Browsers require a user interaction before playing audio; pressing Start counts, so the alarm works without extra permission prompts.
The Pomodoro Technique
Francesco Cirillo's method, developed in the late 1980s and named after a tomato-shaped kitchen timer, is simple: work on one task for 25 minutes, take a 5-minute break, repeat, and after four rounds take a longer break of 15 to 30 minutes. The fixed interval lowers the barrier to starting and makes it obvious when you have drifted into email or social media.
Use the 25-minute preset for work and the 5-minute preset for breaks. Many people adjust the ratio once they know their attention span. 50 minutes of work with a 10-minute break suits deep work, while 15 and 3 works for tasks you are dreading. The timer does not care which you pick; consistency is what builds the habit.
Other everyday uses
Cooking: pasta at 9 to 11 minutes, soft-boiled eggs at 6 to 7, a steak resting for 5 to 10. Workouts: 60-second planks, 90-second rest periods between sets, or a 20-minute AMRAP. Classrooms: timed quizzes, group work, and presentation limits that everyone can see on a projector, where the large display helps.
Meetings and talks: a 5-minute lightning talk or a 2-minute standup update keeps speakers honest. Kids: screen-time limits and tooth-brushing (two minutes, per dentists) are easier to enforce when a neutral timer, not a parent, announces the end. Test prep: SAT sections and other standardized tests are strictly timed, so practicing against the clock is part of the preparation.
Tips for reliable results
Keep the device awake for important timers. The countdown itself stays accurate after sleep, because it checks the clock on wake, but a sleeping phone or laptop cannot play the alarm at the right moment. On phones, keep the screen on or use the built-in clock app for anything critical, such as medication timing.
Check that your device isn't muted and that the tab hasn't been discarded by the browser to free memory, which can happen on low-memory phones with many tabs open. If you need a timer that counts up instead, the stopwatch tool keeps split and lap times.
Privacy and offline use
Everything runs locally in your browser. The page makes no network requests while timing, so it keeps working if your connection drops after it loads. Nothing about your timers is stored or sent anywhere, and closing the tab simply ends the countdown.
Frequently asked questions
How do I set a countdown timer?
Enter hours, minutes, and seconds, or tap a preset, then press Start. Press the same button to pause and again to resume. Reset returns to the time you entered.
Will the timer keep running if I switch tabs?
Yes. It measures time against your device clock instead of counting ticks, so it stays accurate even when the browser slows down background tabs. The remaining time also shows in the tab title.
Does the timer make a sound when it ends?
Yes, three short beeps generated in the browser, plus a 'Time's up' message. Make sure your device is not muted. Some browsers block sound until you have clicked on the page once, which pressing Start does.
What is a 25-minute timer used for?
The Pomodoro Technique: 25 minutes of focused work followed by a 5-minute break, with a longer 15 to 30 minute break after four rounds. Use the 25 min and 5 min presets.
Can I set a timer longer than an hour?
Yes. Enter up to 99 hours. The display switches to hours:minutes:seconds automatically.
Will the timer work if my computer goes to sleep?
The countdown catches up when the device wakes, because it compares against the clock. The alarm sound cannot play while the device is asleep, so keep the screen on for important timers.
Is anything uploaded?
Everything runs in your browser. Nothing you enter is uploaded to a server or stored by us.
How do I set a timer for 20 minutes?
Enter 20 in the Minutes field, leave hours and seconds at 0, and press Start. The timer beeps when it reaches zero.