How to Use the Stopwatch
Use this online stopwatch with lap times for classroom activities, races, science experiments, group rotations, and presentations.
Press Start to begin timing. The readout shows hours, minutes, seconds, and centiseconds (1/100 second).
- Single use: Press Pause to stop the watch. Note the time, then press Resume to continue or Reset to start over.
- Mark laps: Press Lap while the watch is running to snapshot a time interval and continue timing. Lap times appear in the list on the left.
Note: Browser timers and alarms can behave differently if a device sleeps, the tab is inactive, or sound is blocked. Test the timer or stopwatch on your classroom device before using it for exams, assessments, or timed activities.
Classroom Activity Ideas
- Memory test: Make a list of vocabulary or key facts, put students in groups, and time how long each group takes to recall the whole list. Which team is fastest?
- Timed science experiments: Time how long reactions or events take in different conditions and compare. How can students explain the differences?
- Team activity sprint: Set up an activity, switch to fullscreen for the classroom to see, then lap each team or student as they finish.
- Presentation sprints: Give each student one minute to present a topic, then use lap timing to switch quickly between speakers.
FAQs
What's the difference between lap time and total time?
Lap time is a time interval within the total time measured. Pressing Lap simply calculates and marks the time passed since the previous lap. For example, three laps of two, one, and four minutes will make a total time of seven minutes.
Can I set it to stop after a certain time?
No: this stopwatch keeps running until you manually stop it. You can use our online countdown timer to measure a fixed time like an exam session or test.
Will the stopwatch still run if my device goes to sleep?
Usually, yes, although some browsers may not support it. Test it by closing your laptop or device screen for a short time and then checking to see if the stopwatch counted the missing time.
Can I project it for the class?
Yes, just press Fullscreen. The readout fills the screen to be easily visible from the back of the room.