Countdown Timer
Set a time, press Start and get an alarm when it ends, with the time left shown in the tab title.
What this tool does
A countdown timer counts down from a time you set and alerts you when it reaches zero. Enter hours, minutes and seconds or tap a preset, press Start, and keep working in another tab: the time left appears in the tab title and a sound plays when the time is up. It runs in your browser with nothing to install.
Counts down the time you enter, with a progress bar, a pause and resume, and a sound when it finishes.
Calculates the end moment up front, so the remaining time is right even if the tab was throttled.
How to use it
- Enter hours, minutes and seconds, or tap a preset.
- Press Start.
- Pause and Resume if you need to; Reset to start again.
- Leave the tab open - the time left is in the tab title.
- When it reaches zero a sound plays and a message appears.
Why use this timer
Counts down any time from one second to 99 hours, with one-tap presets for 1, 5, 10, 15, 25 and 30 minutes and an hour. A timer keeps work, cooking and study sessions honest. An online timer is always at hand on the device you are already using, and a timer in a tab title is visible while you work in something else.
Why we built it
We built the countdown timer to run from one second to 99 hours with one-tap presets and the time left in the tab title. Use the Pomodoro timer for focus cycles and the online stopwatch to count up.
For a neighbouring job there is also the Online Alarm Clock.
Who this tool is for
- Cooks, students and presenters timing tasks
- Teachers running classroom activities
- Anyone needing an alarm after a set time
When to use it
- Pomodoro-style focus sessions (25 minutes of work, then a break).
- Cooking, tea, laundry and other kitchen timing.
- Timed exams, quizzes, classroom activities and presentations.
- Workouts, rest intervals and meditation.
How it works
When you press Start, the timer notes the exact end moment (now plus the time set). Every fraction of a second it reads the clock and shows how long is left until that moment. Because it never counts ticks, pausing, throttling or a busy page cannot make it run slow.
At zero it plays three short tones with the Web Audio API, which needs no file or network, and shows a message. The tab title updates as it counts so the time is visible from any tab.
Browsers may block sound until you have interacted with the page. Pressing Start counts as that interaction, so the alarm will play. Keep your device's volume up and not muted.
What you give it, and what you get back
| Item | Details |
|---|---|
| Time | Hours (0-99), minutes (0-59) and seconds (0-59), or a preset. |
| Controls | Start, Pause, Resume and Reset. |
| Alarm | Three short tones at zero, if the sound option is ticked. |
| Display | The big clock, a progress bar and the remaining time in the tab title. |
Issues you may run into
| What you see | Why it happens | What to do |
|---|---|---|
| No sound at zero | The device is muted, or the sound option is unticked. | Raise the volume and tick "Play a sound when time is up". |
| Timer shows the wrong time after waking the computer | The device slept and the clock moved on. | The timer uses real time, so it shows zero or the true remainder; set it again if needed. |
| Page title does not change | The browser is hiding or truncating long tab titles. | Check the pinned tab; the big clock still shows the time left. |
| Timer stops when I close the tab | It runs in the page and is not a background service. | Keep the tab open, or use a phone or a physical timer for critical timing. |
Assumptions and limitations
- It runs only while the page is open; it is not a system alarm.
- It needs your device's sound to be on for the alarm.
- It will not wake a sleeping device.
Frequently asked questions
How do I set a timer online?
Enter the time or tap a preset such as 10 min, then press Start. It counts down and plays a sound at zero.
Will it work if I switch to another tab?
Yes. The time left is shown in the tab title and the alarm sounds when it ends, as long as the tab stays open.
Does it play a sound?
Yes, three short tones at zero. Make sure your volume is up and the sound option is ticked.
Is it accurate?
Yes. It calculates the end moment from the clock, so it does not drift even if the tab is throttled.
Can I use it as a Pomodoro timer?
Yes. Tap the 25 min preset for a focus session, then set 5 minutes for the break.
Is it free and private?
Yes. It runs in your browser and nothing is sent anywhere.