Stopwatch
A precise count-up stopwatch with lap and split times. Start, pause and record laps — fully offline.
Open Stopwatch →What is the Stopwatch?
A precise, count-up stopwatch that runs entirely in your browser. It shows a large mm:ss.cs display that updates smoothly, and lets you record numbered laps, each with its own split time and cumulative total. Elapsed time is measured from real timestamps rather than by counting ticks, so it stays accurate even if the tab is busy. Your session — including an in-progress run and all recorded laps — is saved locally, so a refresh picks up exactly where you left off. Nothing is sent to a server and it works offline, even from a downloaded file.
How to use Stopwatch
- Start the clock — Press Start (or the Space bar) to begin counting up from zero. The display shows minutes, seconds and centiseconds.
- Record laps — Press Lap (or the L key) while running to log a numbered lap. Each row shows the split since the previous lap and the cumulative total.
- Pause and resume — Press Pause to freeze the time without losing it, then Resume to carry on from the same point.
- Reset when done — Press Reset (or the R key) to clear the clock and all laps and start a fresh session.
Frequently asked questions
Is the timing accurate?
Yes. Elapsed time is calculated from the browser's clock timestamps, not by counting frames or ticks, so it does not drift if the display slows down.
What is the difference between split and total?
The split is the time since your previous lap, while the total is the cumulative time from the start. The fastest and slowest laps are highlighted subtly.
Will a refresh lose my session?
No. The running state, accumulated time and laps are saved to your browser's local storage, so reloading the page resumes the session correctly.
Are there keyboard shortcuts?
Yes, while the tool is open: Space starts or pauses, L records a lap, and R resets.
Tips
- Use laps to compare repeated efforts — the fastest and slowest splits are marked automatically.
- Pause rather than reset if you only want a short break; Resume keeps your total intact.
- The stopwatch keeps accurate time even if you switch tabs, because it reads the real clock when it returns.