Countdown Timer
A flexible online countdown timer: set hours, minutes and seconds, tap a preset, or count down to a specific date and time. Choose your alarm, run several at once and go fullscreen.
How to use Countdown Timer
- Enter hours, minutes and seconds — or tap a preset such as 5 min, tea or workout round to start instantly.
- Give the timer a label so you can tell your timers apart when several are running.
- Pick an alarm sound, preview it, and set how many times it should repeat.
- Press Start. Add more timers at any time; each one counts down independently.
- Use the fullscreen button for a room-readable countdown on a big screen or projector.
About Countdown Timer
A countdown timer is one of those tools that only feels good when the details are right. The number has to be legible from the other side of the kitchen, starting a five-minute timer should take one tap rather than three fields of typing, the alarm must actually be audible, and it must not lie to you about the time when the tab has been in the background. This one handles all four: quick presets from one to sixty minutes, named presets for tea, eggs and workout rounds, a fullscreen mode for a projector or a phone propped against a mug, and drift-free timing.
Timing is derived, never decremented. The moment you press Start, the timer records the exact millisecond it should finish and every frame simply asks how far away that is. That is why the countdown survives tab throttling, sleep and reloads — and why closing the page and reopening it restores exactly the right remaining time. The optional spoken announcement uses the browser's built-in speechSynthesis voice, and browser notifications can flag the finish visually if your sound is off.
Because everything runs in the page, several timers can run at once without any of them interfering — useful in a kitchen, a lab, a classroom, or an interval workout where work and rest have different lengths. Nothing is uploaded: labels, durations and sound preferences live in your browser only. And since the whole thing is a single page with no dependencies to fetch at run time, it keeps working after the connection drops.
Frequently asked questions
Will the countdown keep running if I switch tabs?
Yes. Each timer stores an absolute end time and works out what is left from the system clock, so background throttling cannot make it drift. Switch away for twenty minutes and the timer is exactly twenty minutes further along when you return.
Will the alarm sound if my phone screen is locked?
Usually not. Mobile browsers suspend the page when the screen locks or you switch apps, and a suspended page cannot play audio, so the alarm fires when you next open the tab. On a desktop, audio from a background tab plays normally. For a locked phone, your device's built-in clock app is the reliable option.
Can I run more than one timer at once?
Yes — add as many as you like. Each has its own label, duration and alarm sound, and they all count down independently. It is the fastest way to cook three things that finish at different times.
What happens if I refresh the page?
Running timers are restored. Because the end time is stored as an absolute timestamp rather than a remaining duration, a reload picks up exactly where the clock actually is. Timers that expired while the page was closed are shown as finished rather than sounding an alarm late.
Can I count down to a specific date and time?
Yes. Switch the timer to date-and-time mode and pick the moment — a deadline, a launch, an exam, a flight — and the countdown shows days, hours, minutes and seconds remaining in your local time zone.
Is the alarm an audio file?
No. Every alarm tone is generated live with the Web Audio API from oscillators and gain envelopes, which is why it starts instantly, is never blocked by an autoplay policy, adds nothing to the page weight and works with no internet connection.
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