Online Countdown Timer with Alarm
Set your timer
Background alerts are optional. Device sleep, browser suspension, silent mode, volume, and permission settings can prevent sound, vibration, or notifications.
Timer
Shortcuts: Space start/pause/resume · R restart · F fullscreen · Esc exit focus mode.
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Named multiple timers
Add independent timers for cooking steps, classroom groups, or concurrent tasks.
Popular timer setups
Choose a common task to load it into the main timer. Your preset setting decides whether it starts immediately.
| Use case | Suggested time | Set timer |
|---|---|---|
| Pasta | 10 minutes | |
| Pomodoro focus | 25 minutes | |
| Presentation practice | 5 minutes | |
| Workout rest | 60 seconds |
How this browser timer works
The timer stores its target duration and subtracts elapsed time measured by the browser’s monotonic performance.now() clock. If an inactive tab refreshes less often, the visible digits may pause briefly, then catch up from elapsed time when the browser runs the page again.
Alerts, inactive tabs, and device sleep
Sound is enabled by default, but it begins reliably only after you press Start or Preview because browsers require a user interaction before audio. Optional notifications, vibration, and screen wake lock depend on browser and device support. A locked phone, suspended tab, silent mode, low-power setting, denied permission, or closed browser can delay or prevent an alert, so do not use this page for safety-critical timing.
Timer, stopwatch, or date countdown?
Use a timer when you know the duration and want an alarm at zero. Use a stopwatch to measure how long an activity takes. Use a countdown to a date for a fixed calendar event such as a birthday or deadline.
Accuracy and browser behavior
Total duration is calculated as hours × 3,600,000 + minutes × 60,000 + seconds × 1,000. Remaining time is original duration − elapsed time, never below zero. Rendering is separate from elapsed-time calculation, so throttled background-tab display updates do not intentionally add time.
Last tested: 18 July 2026 with automated timer-logic checks. Designed for current Chrome, Safari, Firefox, iOS, and Android browsers; audio, notification, vibration, floating-window, fullscreen, and wake-lock support varies and should be confirmed on the device used.
Countdown timer FAQ
How do I set a timer for five minutes?
Press the 5m preset for a one-tap start. To load it without starting, change “When a preset is chosen” to “Load only.” You can also enter 5 in Minutes and press Start.
Will the alarm sound in another tab?
Usually, if you started or previewed audio first and the browser keeps the page active. Browser suspension, device sleep, silent mode, and volume settings can still prevent it.
Will it work when my phone locks?
It may not. Mobile browsers can suspend web pages when the screen locks. Keep the page open and try “Keep screen awake” where supported, but use the phone’s native alarm for critical reminders.
Can I pause and resume?
Yes. Pause preserves the remaining time, and Resume continues from it.
Can I repeat the timer?
Yes. Turn on “Repeat automatically,” or press Restart after it finishes.
Is it free and private?
Yes. The timer requires no account or payment. Timer names and settings stay in this page and are not submitted by the timer controls.
How accurate is it?
It calculates from elapsed monotonic browser time rather than counting visual frames. Background throttling can delay a display update or alert even though the remaining-time calculation catches up.
Can I run more than one timer?
Yes. Use “Add another timer” to create named, independent timers, each with its own duration, alarm choice, progress, and controls.