Online Timer — Free Countdown Timer with Alarm

A Countdown Timer and Stopwatch in One Tab

Two tools in one page: a countdown that counts down to an alarm, and a stopwatch that counts up from zero. Switch between them in Settings — no separate app, no account, nothing to install.

Where People Use It

Presentation and stream overlays

No app to install and no account — if you're already presenting or streaming from a laptop, it's another browser tab away instead of a reason to switch to your phone, and there's no ad breaking up the countdown mid-session.

Timed work and study blocks

A plain duration timer for anything with a hard stop — a timed test, a reading block, a meeting agenda item — without the Pomodoro structure of rounds and breaks.

Workouts, cooking, and quick intervals

Punch in minutes and seconds for a rest period, a cook time, or a stretch hold, and the alarm tells you when it's done so you don't have to watch the screen.

Tracking elapsed time

Switch to Stopwatch when you don't have a duration to set — just want to know how long a task, a call, or a workout actually took.

How to Use

Four steps, whichever mode you need.

Pick a mode

Countdown and Stopwatch both live under Settings → Mode — switching resets the display, and your last duration is remembered for next time.

Set your time

In Countdown mode, enter hours, minutes, and seconds — up to 99 hours — while the timer is paused.

Start, and let the alarm tell you

Hit play and walk away. When a countdown hits zero it plays an alarm automatically, unless you've turned Alarm Sound off.

Go fullscreen for a session

Fullscreen clears the browser chrome for stream or presentation use; Keep Screen On stops the display from dimming mid-session.

Features

What you're actually getting, feature by feature.

Countdown & Stopwatch in one

One Mode toggle in Settings switches between counting down to zero and counting up from zero — no separate page or URL.

Custom H:M:S duration

Set hours, minutes, and seconds independently for a countdown up to 99 hours.

Alarm sound toggle

A short alarm tone plays automatically when a countdown reaches zero — or turn it off for a silent timer.

Fullscreen mode

Clear the browser tab away for a distraction-free, presentation-ready display.

Keep screen on

The Wake Lock API stops the screen from dimming or sleeping partway through a long countdown.

Color themes

Pick from the same LED color set as the rest of the site's clocks, saved locally for next time.

FAQ

The questions that come up most about this tool.

Does this have a stopwatch, not just a countdown?

Yes — open Settings and switch Mode from Countdown to Stopwatch. It counts up from zero and keeps running until you stop it; it's the same page, not a separate tool.

Can I use this as an on-screen timer for a presentation or livestream?

Yes. Set a countdown, go fullscreen, and the display works as a visible on-screen timer for a talk, a slide, or an OBS browser source — no plugin or separate app needed.

Does the stopwatch mode track lap times?

Not this one — it tracks total elapsed time only. For lap splits, use the dedicated Stopwatch page instead.

Will it keep counting if I switch tabs?

Yes, the countdown or stopwatch keeps running in a background tab. Turn on Keep Screen On if you also need the display to stay lit and visible.

What's the difference between this and the Pomodoro Timer?

This is a plain single-duration timer or stopwatch. The Pomodoro Timer adds structure on top — repeating focus and break rounds with its own chime sounds.

From the Blog

Need lap times, not just elapsed time? See the dedicated Online Stopwatch. Need repeating focus and break rounds instead of a single duration? See the Pomodoro Timer. Need to wake up at a specific time of day instead of after a duration? See the Online Alarm Clock.