Stopwatch
Measure elapsed time with lap splits, stats, and export.
The Online Stopwatch provides millisecond-level elapsed time measurement with lap split capabilities. Whether timing athletic workouts, cooking recipes, presentations, or software processes, it delivers an intuitive interface with automatic highlights for best and slowest split times.
How to Use the Stopwatch
- Click the "Start" button to begin timing from zero. The button will toggle to "Pause".
- While running, click "Lap" to record the current split. The total elapsed time and individual lap duration appear in the lap table below.
- Click "Pause" to temporarily halt the timer without losing your recorded splits. Click "Resume" to continue timing.
- Click "Reset" when paused to clear the timer display and reset all recorded lap times.
- Click "Copy" above the lap history table to export all lap splits and totals directly to your clipboard.
Key Features & Precision
Millisecond Precision
Tracks elapsed hundredths of a second (centiseconds) for high accuracy in sports and scientific measurement.
Best & Slowest Lap Badges
Automatically highlights your quickest split with a green "Best" badge and slowest with a red "Slow" badge.
Background Tab Persistence
Uses absolute system timestamps (`Date.now()`) rather than simple interval counting, so elapsed time remains 100% accurate even if you switch tabs or minimize the browser.
One-Click Clipboard Export
Easily paste formatted split data into spreadsheets, training logs, or documents.
Common Use Cases
Athletic Training & Running
Measure interval splits during track laps, circuit workouts, cycling drills, or swimming sets.
Speech & Presentation Practice
Rehearse slide decks and keynotes to ensure each section fits within strict conference time limits.
Usability & Process Testing
Time user workflows and onboarding steps during product evaluations and QA tests.
Frequently Asked Questions
Does the stopwatch slow down if I switch to another browser tab?
No. The stopwatch calculates elapsed time by comparing the initial start timestamp against the current system time whenever the screen updates. Background tab throttling does not affect timing accuracy.
How many laps can I record?
You can record dozens of consecutive laps. The scrollable table keeps all entries accessible with relative split calculations.
Can I copy the recorded lap times into Excel or Google Sheets?
Yes. Clicking the "Copy" button formats all laps with their individual split and cumulative times, ready to paste directly into spreadsheets.