Does it work in a background tab?

Yes. The timer keeps counting in background tabs; the alarm fires when the time elapses even if you've switched away. (Caveat: very long countdowns + sleeping laptop will pause until you wake — the timer relies on the JS event loop, which doesn't run when the OS suspends the browser.)

Why does the alarm sometimes not play?

Modern browsers block autoplay of audio without user interaction. The first time you start a timer in a fresh browser session, the click counts as interaction and unlocks audio. If you reload the page and the alarm doesn't fire on the next timer, click somewhere on the page (the Start button alone is enough) to re-establish audio permission.

Can I customize the alarm sound?

Not in this version — the alarm is a built-in pleasant chime. For custom sounds use a downloadable timer app (most desktop OSes have one built-in). Some users also prefer iOS / Android timer apps for the broader sound options.

Does it persist across page refreshes?

No — the timer resets if you refresh. For a persistent timer that survives reloads, your computer's native timer app or a phone timer is more reliable.

Why does my displayed time slightly drift?

JavaScript timers (setTimeout / setInterval) aren't perfectly accurate — they can drift by a few milliseconds per second under load. The display updates every second based on the system clock (not by accumulating drift), so the END time is correct even if individual updates skip. Don't expect sub-second accuracy from a browser timer.

Can I save preset timers?

The quick-pick buttons cover the most common durations. For frequently-used custom durations (e.g. 23 minutes), save bookmarks with the URL parameter (e.g. ?duration=1380 for 23 minutes if the tool supports it). Otherwise type the duration each time.

Productivity · Free tool

Online Timer

Set a free online countdown timer with a loud audible alarm. Configure hours, minutes, and seconds that will run even in a background tab with no sign-up.

Updated June 2026

10:00

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What it does

Free online countdown timer with audible alarm. Set your duration in HH:MM:SS format (or with quick-pick buttons for common durations: 5 min, 10 min, 15 min, 30 min, 1 hour), press Start, and the timer counts down with a clean visual display. When time reaches zero, an alarm sound plays. Pause and resume any time. The timer works in background tabs — switch away to do other work; the alarm fires when time’s up.

The use cases are universal: cooking and baking (when your stove timer is taken or you’re away from the kitchen); workout intervals (HIIT, EMOM, AMRAP structure); focus sprints (Pomodoro 25-min, deep- work 90-min); meeting time-boxing (each agenda item gets a hard cap); parenting (screen-time limits, turn- taking, “5 more minutes” that means it); presentation rehearsal (practice within your allotted slot); studying (timed practice sets, test simulation); quick reminders (the “tea steeping for 4 minutes” or “phone in pocket for the next hour” pattern).

This page is the same timer as our /countdown-timer tool — the duplicated URL captures “online timer” search intent specifically (one of the highest-volume timer-related search queries). Both URLs are stable and bookmarkable; if you find yourself using this every day, bookmark the one you prefer typing.

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Paste this snippet into any page. Loads on-demand (lazy), no tracking scripts, and sized to most dashboards. Replace the height to fit your layout.

<iframe src="https://freetoolarena.com/embed/online-timer" width="100%" height="720" frameborder="0" loading="lazy" title="Online Timer" style="border:1px solid #e2e8f0;border-radius:12px;max-width:720px;"></iframe>

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How to use it

Set the duration: type into HH:MM:SS, or click a quick-pick (5m / 10m / 15m / 30m / 1h).
Press Start. The countdown begins; the visible clock updates each second.
Pause any time with the Pause button (timer stops, doesn't reset). Resume to continue from where you paused.
When time reaches zero, an audible alarm plays. The visual indicator flashes. Click Stop to silence the alarm and reset.
If you switch tabs during the countdown, the timer keeps running. The alarm still fires when time elapses (modern browsers permit audio playback for previously-interacted-with tabs).

When to use this tool

Any time you need a hands-free countdown without dragging out your phone.
Teaching kids time concepts ('we have 10 more minutes').
Cooking when multiple things are timed at once and the kitchen timer is taken.
Pomodoro focus sessions, HIIT workouts, meditation intervals.

When not to use it

Highly-precise scientific timing — browser timer drift can be a few milliseconds per minute. For sub-millisecond precision use a hardware timer.
Background timers when your laptop sleeps — the OS may suspend the browser; the timer pauses too. Keep the laptop awake or use a phone timer for sleep-tolerant timing.
Multiple simultaneous timers — this is single-timer. For parallel timers (3 batches in different ovens), open multiple tabs.

Common use cases

Onboarding a colleague who needs the same calculation/conversion
Verifying a number or output before passing it on
Quick use during a typical workday
Pre-decision sanity-check on inputs and outputs

Frequently asked questions

Does it work in a background tab?: Yes. The timer keeps counting in background tabs; the alarm fires when the time elapses even if you've switched away. (Caveat: very long countdowns + sleeping laptop will pause until you wake — the timer relies on the JS event loop, which doesn't run when the OS suspends the browser.)
Why does the alarm sometimes not play?: Modern browsers block autoplay of audio without user interaction. The first time you start a timer in a fresh browser session, the click counts as interaction and unlocks audio. If you reload the page and the alarm doesn't fire on the next timer, click somewhere on the page (the Start button alone is enough) to re-establish audio permission.
Can I customize the alarm sound?: Not in this version — the alarm is a built-in pleasant chime. For custom sounds use a downloadable timer app (most desktop OSes have one built-in). Some users also prefer iOS / Android timer apps for the broader sound options.
Does it persist across page refreshes?: No — the timer resets if you refresh. For a persistent timer that survives reloads, your computer's native timer app or a phone timer is more reliable.
Why does my displayed time slightly drift?: JavaScript timers (setTimeout / setInterval) aren't perfectly accurate — they can drift by a few milliseconds per second under load. The display updates every second based on the system clock (not by accumulating drift), so the END time is correct even if individual updates skip. Don't expect sub-second accuracy from a browser timer.
Can I save preset timers?: The quick-pick buttons cover the most common durations. For frequently-used custom durations (e.g. 23 minutes), save bookmarks with the URL parameter (e.g. ?duration=1380 for 23 minutes if the tool supports it). Otherwise type the duration each time.

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