How to use the classroom timer
Pick Countdown, Pomodoro or Stopwatch from the switch at the top of the widget, set a duration or preset, then press Start. To keep the timer visible while you switch to slides, a PDF, or another browser tab, use “Keep on top” – it pops the timer into its own small window that floats above everything else on your screen. Everything runs from your own browser; nothing is uploaded anywhere.
What each control does
- Countdown / Pomodoro / Stopwatch – switches the timer’s mode. Each remembers its own settings.
- Preset chips (Countdown only) – quick durations from 5 to 60 minutes; click one before pressing Start.
- Label – an optional note (e.g. “Silent reading” or “Group discussion”) shown under the digits and mirrored in the browser tab title.
- Start / Pause / Resume – runs or pauses the current timer. Pausing freezes the remaining time exactly; it does not lose track of it.
- Reset – returns the current mode to its starting point. It does not change your saved settings.
- Lap (Stopwatch only) – records a split without stopping the clock.
- Keep on top – pops the timer into a small always-on-top window (Chrome and Edge 130+, and Firefox 151+ on desktop). On Safari desktop, iPad and iPhone it falls back to a display-only floating video window instead, since Safari does not support interactive pop-out windows for web pages. If neither is available, a draggable floating panel stays on top of this page instead – honest degradation, not a broken button.
- Fullscreen – large, high-contrast digits for a projector or a shared screen. Some embedded contexts (for example certain iframes) do not allow fullscreen; the widget will tell you rather than sit there doing nothing.
- Settings – alarm sound (with a “test sound” button), volume, light/dark theme, phase-change announcements for screen readers, and the three Pomodoro durations.
- Copy link – copies a link to this exact timer (mode, duration and label) so you can paste it into Google Classroom or share it with a colleague.
Pomodoro: the 25/5 method in one minute
The Pomodoro Technique is a time-management method: work in focused 25-minute blocks, take a 5-minute break, and after every four blocks take a longer 15-minute break. The short breaks protect concentration; the long break prevents burnout across a study session.
Ways teachers use it
- Timing lesson transitions between activities without losing the class’s attention to a phone.
- Silent reading or independent work blocks, with the label showing what students should be doing.
- Exam-style practice under real time pressure, popped out and visible while you circulate the room.
- Group discussion or station rotations, with a short chime marking each rotation.
- Pack-up warnings before the end of a lesson.
- Keeping presentations and student talks inside their allotted time, projected in fullscreen mode.
Ways students use it
- Pomodoro revision sessions – 25 minutes on, 5 minutes off, with a long break every fourth round.
- Enforcing break discipline so a “quick break” does not become the rest of the evening.
- Timed past-paper practice under exam conditions.
- A stopwatch with laps for timing rehearsals or presentation run-throughs.
FAQ
Does the timer keep running if I switch to another tab?
Yes. The timer works out how much time is left from the clock, not by counting down a fixed number of steps, so it finishes on time and the alarm still sounds even if the browser tab has been in the background for a while.
Why does “Keep on top” look different on my phone or on Safari?
Only Chrome, Edge and Firefox on desktop currently support pop-out windows for ordinary web pages. Safari and mobile browsers do not, so the timer falls back to a display-only floating video window on Safari, or a floating panel on this page everywhere else. This is a genuine browser limitation, not a bug in the timer.
Is anything saved or sent anywhere?
Your preferences (sound, volume, theme, Pomodoro durations) and a timer’s label are stored in your own browser’s local storage so they are there next time you visit. Nothing is ever sent to a server.
What happens if I accidentally refresh the page?
If a timer was running or paused, you will see a “Resume timer?” banner with the time that was left, so a refresh does not cost you the session.
Can I share a preset timer with my students?
Yes – use “Copy link” to copy a URL that opens this page directly into the mode, duration and label you have set up, ready to paste into Google Classroom or a lesson plan.
Can I embed this timer on another site?
Yes – add ?chromeless=1 to the page URL for a chrome-free version suitable for an iframe. See the embed snippet below.
Will the alarm still play if my laptop goes to sleep?
If the deadline passes while the computer is asleep, the timer shows the correct finished state as soon as you wake it, rather than a stale countdown. The alarm itself needs the tab to be open and the computer awake to be heard, the same as any browser-based timer.
Embed this timer
Paste this into your own site to embed a chrome-free version of the timer:
<iframe src="https://jonathanseet.net/educator/tools/classroom-timer/?chromeless=1" width="360" height="640" style="border:0" title="Classroom Timer"></iframe>Your preferences and any timer label are stored in your own browser, never sent to a server. Free to use.