Online Stopwatch
Start, stop and record laps. Shows hundredths of a second and keeps the right time in the background.
| Lap | Split | Total |
|---|
Keyboard: Space = start or stop, L = lap, R = reset.
Everything runs in your browser. Nothing you do here is sent to or stored on a server.
How to use the stopwatch
- Press Start (or the Space key) to begin timing.
- Press Lap (or L) to record a lap without stopping the clock. Each lap shows its own time (the split) and the total time so far.
- Press Stop to pause, then Resume to continue, or Reset to clear everything.
- Use Copy laps to paste the lap table into a spreadsheet or a message.
Split time and total time
A split is the time since the previous lap. The total is the time since you pressed Start. If your first lap is 30.00 seconds and your second lap button press happens at 1:05.00, the second split is 35.00 seconds and the total is 1:05.00. When you record three or more laps, the fastest and slowest splits are marked so you can compare them quickly.
Accuracy
The stopwatch measures time by comparing the clock at the moment you press a button with the clock when you started, instead of adding up timer ticks. That means it keeps the right time even when your browser is busy or when the tab is in the background. The display shows hundredths of a second, but the precision you can achieve is limited by your own reaction time, the screen refresh and the delay between a button press and the browser registering it, which is usually a few hundredths of a second or more. For sports where fractions of a second decide the result, use certified timing equipment.
Good uses for an online stopwatch
- Timing workouts, intervals and rest periods
- Presentations, speeches and practice runs
- Cooking steps and lab experiments
- Comparing how long a task takes from one attempt to the next
Frequently asked questions
How do I record lap times?
Start the stopwatch, then press Lap (or the L key) each time you want to mark a lap. Each lap is listed with its split time and the total time.
Does the stopwatch keep running if I switch tabs?
Yes. Elapsed time is calculated from the clock, so it stays correct while the tab is hidden. The tab title also shows the running time.
How accurate is the stopwatch?
The clock is accurate to a few milliseconds, but the time you record depends on when you press the button, so expect a few hundredths of a second of human and device delay.
Can I copy my lap times?
Yes. Press Copy laps and paste the table into a spreadsheet, note or message.
Is there a keyboard shortcut?
Space starts or stops the stopwatch, L records a lap, and R resets it, as long as you are not typing in a field.
Does the screen stay on while timing?
Where your browser supports it, the page asks your device to keep the screen awake while the stopwatch is running, and releases it when you stop.