Millisecond-precise stopwatch with unlimited lap recording — start, pause, reset, and record laps directly in your browser.
Also count down with our Countdown Timer or calculate dates with the Age Calculator.
This browser-based online stopwatch uses the performance.now() API for millisecond precision — significantly more accurate than setInterval-based timers that can drift over time. It works as a lap timer, split timer, and sports stopwatch for athletes, coaches, students, and professionals who need accurate time tracking without installing an app.
Athletes and coaches use stopwatches to time sprints, swimming laps, cycling intervals, and running splits. The lap function records each split time as you go, building a list of every interval so you can compare performance across laps at the end of a session. Unlike a physical stopwatch, this browser version never needs a battery replacement and is always with you on any device that has a browser.
Students use stopwatches for timed study sessions, practice tests, and managing time during exam preparation. Tracking exactly how long each section of a practice test takes helps identify which topics need more time and whether the overall pace is on track for the real exam. The lap function turns a single stopwatch into a per-section timer without needing to reset between questions.
Professionals use stopwatches to time presentations, client calls, production workflows, and QA testing cycles. A developer timing an API response or a build process, a teacher timing a student speech, or a project manager measuring a stand-up meeting can all use this tool without switching apps or installing anything. Once loaded, the stopwatch works entirely offline — the JavaScript continues running in your browser tab even without an internet connection, making it reliable in low-connectivity environments like gyms, outdoor tracks, or field sites.
The lap list displays newest entries at the top so you can see the most recent split without scrolling — useful when timing many laps in quick succession during a race or workout. All timing data stays in the current browser session only; nothing is saved or transmitted anywhere.