Online Stopwatch
Start timing instantly. Record laps, compare split times, and save your results.
Lap times
0 completed laps| Lap | Lap time | Split time | Label |
|---|
Make this session yours
No account neededSaved on this device · Pause to save · Up to 20 sessions
Saved sessions 0
Key takeaways
- The stopwatch counts up from zero. Space starts and pauses, L records a lap, F opens full screen.
- Time comes from your browser's steady clock, not from counting screen updates, so it keeps going when the tab is in the background.
- If the device sleeps or its clock jumps, you get a "Timing uncertainty" warning instead of a silent error.
Simple by design. Ready for anything.
Use this free online stopwatch for a practice run, a kitchen task, a presentation or a quick comparison. No account, no setup and no countdown. Need to count down instead? Our sister site Online Timer sets a countdown with an alarm, also free and without an account.
- Start with a single click.The stopwatch counts up from zero. Space starts or pauses when you are not editing a field or using a control.
- Mark the moments that matter.Press Lap or L to record a completed lap without interrupting timing.
- Take your results with you.Add a name, copy a summary or download CSV. Pause to save a session on this device.
How accurate is an online stopwatch?
As accurate as your button presses. The clock itself is precise. The stopwatch reads performance.now, a steady clock in the browser that is not changed when the computer's time is adjusted. The biggest error is the moment you press Start, Lap or Pause.
| What can affect the time | What Online Stopwatch does |
|---|---|
| Your reaction when you press a button | Nothing can remove it; press the same way each time |
| The screen updating | Redraws about every 32 ms with hundredths, 100 ms without; the time underneath is not rounded |
| The tab in the background | Keeps counting from the clock and catches up when you return |
| The device sleeping or its clock changing | Compares two clocks, keeps the larger estimate if they differ by more than 2 seconds, and warns you |
| Very long sessions | Stops at 999:59:59.99 and asks you to export |
Guides: How to use a stopwatchSplit times for runningHow accurate is it?Study stopwatch
A few useful answers
What is the difference between lap and split?
A lap is the active time since your last mark. A split is the total active time from the start. Marks at 00:12.40 and 00:25.10 give lap times of 00:12.40 and 00:12.70.
Does paused time count?
No. Pause freezes active time. Resume continues the same unfinished lap. Pausing never adds a completed lap.
What is included in a CSV download?
Your session name and recorded laps, with labels, lap times, split times and numeric milliseconds. Unfinished time is not added as a lap. With no recorded laps, CSV contains column headings only; Copy results includes your total time. Formula-like names and labels are prefixed with an apostrophe for spreadsheet safety.
Where are my results saved?
The active session is kept in this tab when browser storage is available. Save session keeps up to 20 paused sessions on this device. Nothing is uploaded by the app. Clearing browser data can remove your results.
Can I use fullscreen or keep the screen awake?
Choose Open Full Screen and leave with Exit Full Screen or Escape. Unsupported browsers use an expanded window view. Keep screen awake is optional and works only when the browser allows it during visible, active timing. It does not promise background or locked-screen operation.
How accurate is the stopwatch?
This is a manual timing tool, not certified competition timing. Hundredths describe the display, not the accuracy of your reaction or device. Background rendering may stop while elapsed time continues. Reloads use the system clock; sleep or clock changes can make recovery uncertain and are flagged. The maximum is 999:59:59.99.
Can I use this stopwatch offline?
After the first successful cache download, the stopwatch and these pages can work offline. Browser storage settings can prevent this. Updates wait until old app tabs have closed.
Do I lose my time if the page reloads?
Usually not. The running session is saved in the tab and recovered after a reload. Closing the tab removes it unless you saved it.