Online Stopwatch
Free online stopwatch with millisecond precision and lap timer
Lap Times
| Lap | Lap Time | Total Time |
|---|
Keeps running — even after a reload
Your stopwatch and laps are saved automatically in this browser. Reload the page or come back tomorrow: the timer picks up right where it left off, and finished sessions are archived locally. Nothing is uploaded to any server.
Session Stats
Recent Sessions
Reset the stopwatch to archive a finished session here.
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Use Tool →How to Use
Start the Stopwatch
Click Start or press the Space bar. The stopwatch begins counting immediately with millisecond precision.
Record Laps
Press Lap (or the L key) at any moment while running to capture a split time without stopping the clock.
Review Your Times
Stop with Space or Pause, then review lap times. The fastest and slowest laps are highlighted automatically, and press Reset to clear.
About This Tool
Free online stopwatch with millisecond precision and lap timer
This online stopwatch runs entirely in your browser with centisecond (1/100 second) precision, making it accurate enough for sports training, cooking, lab work, and games. Laps are recorded instantly without interrupting the timer.
No download or registration is required. Keyboard shortcuts (Space, L, R) let you operate the stopwatch hands-free, and lap statistics update live as you record splits.
Millisecond Precision
Built on the browser high-resolution timer, accurate to 1/100 of a second — the precision standard for track and swimming events.
Smart Lap Tracking
Every lap is numbered with split and total times. The fastest and slowest laps are automatically highlighted for instant analysis.
Keyboard Shortcuts
Control everything without leaving the keyboard: Space to start and pause, L to record laps, and R to reset.
Learn More
Sports & Racing — Time sprints, laps, and races, then compare split times to measure consistency and pacing.
Fitness Training — Track rest periods between sets and circuit stations with hands-free keyboard control.
Teaching & Labs — Use it as a classroom timer for experiments, quizzes, and timed activities on any shared screen.
Frequently Asked Questions
Authoritative Sources
Standards and research behind this tool, from official specifications to peer-reviewed studies.
Precise timing matters more than most people assume: lab experiments, cooking, sports intervals, and speech practice all depend on reliable elapsed time. The stopwatch and countdown tools on this site use the browser's High Resolution Time API standardized by the W3C — the same monotonic-clock specification that professional timing software builds on. For calendar math such as days between dates, the calculations follow the Gregorian calendar rules maintained by metrology institutes such as NIST, the US authority for official timekeeping.