Classroom Timer Online and Stopwatch
Run a clear full-screen countdown for lessons, activities, presentations, or focused work, then switch to a stopwatch when you need elapsed time.
Use the full-screen classroom timer
Choose a 1, 2, 5, 10, 20, 30, or 60 minute preset for a question, transition, group activity, reading block, presentation, or focused work period. Select Full screen when the countdown needs to remain visible across a room. The timer has no student names, accounts, advertising controls, or classroom data collection.
Test the alert and device volume before the activity begins. Keep the tab open and prevent the device from sleeping. A browser timer is convenient for ordinary activities, but it should not be the only safeguard for exams with formal timing rules, medication, heat, machinery, childcare, or another safety-critical task.
How to use the countdown timer
- Enter minutes and seconds or choose a preset.
- Press Start and leave the tab open.
- Pause and resume with the same button when needed.
- Use Reset to return to the selected duration.
- Allow sound on the device if you want to hear the finishing alert.
Use the stopwatch and laps
Switch to Stopwatch, press Start, and add laps without stopping the main clock. A stopwatch measures elapsed time rather than time remaining. Use it for practice rounds, demonstrations, exercise intervals, or any task where the finish time is not known in advance.
Quick timer presets
The page includes 1, 2, 5, 10, 20, 30, and 60 minute presets. You can also enter any duration up to 999 minutes and 59 seconds. The countdown uses a target end time rather than subtracting one second per animation frame, which helps it recover correctly after a temporarily slow tab.
How browser timing works
The countdown stores the intended finish time and recalculates the remaining duration against the current clock. Browsers may slow a background tab, so the visible display can update less often until you return. The stopwatch uses a high-resolution elapsed-time clock while the page is open. Neither mode sends timing data to ToolZone or requires an account.
Timer questions
Will the timer keep running in another tab?
The target finish time remains accurate while the page stays open, although the visible display may update less often in a background tab. Return to the page to see the current remaining time.
Why did I not hear the alert?
Check device volume, browser sound permissions, silent mode, and whether the tab was suspended or closed. The visual display still reaches zero when the page can continue running.
Can I time longer than one hour?
Yes. Enter the total minutes, up to 999, and any additional seconds. The display adds an hours section automatically for longer durations.
Related time tools
Use the Clock with Milliseconds for a live local clock and precision count-up view, or the Date Difference Calculator for calendar intervals.