How to use it on a big screen
- Open full screen with the button above or the F key. Press Esc or F again to leave.
- Start and stop with Space, so a wireless keyboard or presenter clicker that sends a space works as a remote. L records a lap without leaving full screen.
- Pick the digits you need: tenths (0.1 s) are easiest to read from the back of a room; hundredths and milliseconds suit close-up timing.
- The screen stays on while the stopwatch runs on browsers that support the Screen Wake Lock API (current Chrome, Edge and Safari), so a phone or tablet doesn't dim mid-session.
How big are the digits?
In full screen the readout scales to the screen: the minutes and seconds are about a quarter of the screen width and up to roughly 44% of its height, and the fraction digits about half that. On a 55-inch TV the main digits come out at roughly 20 cm tall, readable from the back of a gym. On a phone, turn it sideways for the largest numbers.
| Setting | Where it helps |
|---|---|
| Projector or TV via HDMI | Classroom races, presentations, timed tests and quizzes |
| Tablet on a stand | Gym circuits, physio holds, cooking and lab steps |
| Phone in landscape | Trackside or poolside, a big readout that a swimmer can see from the water |
| Second monitor | Speedruns, streaming overlays captured from a browser window, time studies |
The timing doesn't depend on the display: elapsed time is computed from the moment you pressed Start, so it stays correct if the tab is hidden or the screen sleeps. Read the accuracy guide for what the extra digits do and don't tell you. To time several people at once on the same screen, use multiple stopwatches; to count laps toward a target, use the lap counter.
Questions people ask
How do I make the stopwatch full screen?
Press the Open full screen button or the F key. The digits then fill the screen. Press Esc or F to exit. On iPhone, where web pages cannot enter true full screen, the page switches to a large-digit view instead; turn the phone sideways for the biggest numbers.
Will my screen turn off while the stopwatch is running?
On browsers that support the Screen Wake Lock API (current Chrome, Edge and Safari) this page asks the device to keep the screen on while the stopwatch runs and releases it when you stop. Elsewhere, the timing stays correct even if the screen sleeps; only the display pauses.
Can I control it with a presenter remote?
Many presenter clickers can send a Space or arrow key; if yours sends Space, it starts and stops the stopwatch. L records a lap and R resets while stopped.
Can I show it on a TV or projector?
Yes. Open this page on a laptop connected by HDMI or cast the browser tab, then press F. Tenths of a second are easiest to read from far away.
Does full screen change the accuracy?
No. The stopwatch calculates elapsed time from timestamps, not from screen refreshes, so full screen, a hidden tab or a dimmed display do not change the recorded time.