Free classroom tool
Stopwatch
A big, clear stopwatch with laps, for PE, science practicals and any lesson where you need to time something up.
Keep a running time
Use the stopwatch to time a sprint, a reaction experiment, how long a class takes to line up, or a chemical reaction. Press Lap to record split times without stopping the clock, and the list keeps every lap with the time since the previous one.
Easy to read from the back
The numbers are large and high-contrast. Press Fullscreen to fill the board, and press the space bar to start or stop without reaching for the mouse.
Accurate and private
It measures real elapsed time, so it stays accurate even if the tab is in the background. Nothing is sent anywhere.
How accurate is it?
It displays to a tenth of a second and is based on your device's clock, which is accurate enough for classroom use.
Can I record lap times?
Yes. Press Lap at any time. Each lap shows the split time and the total.
Does it keep running if I switch tabs?
Yes. It works from the start time rather than counting ticks, so it never falls behind.