Online Stopwatch
High-precision millisecond timing and lap recording.
Includes a distraction-free fullscreen mode.
About the Online Stopwatch
This tool is a free, high-precision online stopwatch capable of measuring time down to the millisecond. Whether you need to manage your study time, measure lap times for sports, or practice for a presentation, it handles any situation that requires precise timekeeping. No app installation is required—it is instantly accessible from any browser on smartphones, tablets, or desktop PCs.
Additionally, it features a Fullscreen Mode that hides all ads and unnecessary elements, displaying only the timer in a large format. This makes it incredibly easy to read from a distance.
How to Use the Stopwatch
Start Timing
Click the "Start" button to begin timing in milliseconds. The screen is automatically prevented from going to sleep while running (on supported browsers).
Record Lap Times
Click the "Lap" button while the timer is running to log the exact moment in the list below. The split time from the previous lap is also calculated automatically.
Stop and Reset
Click the "Stop" button to pause the timer. You can then "Resume" from where you left off or click "Reset" to return the time to zero and clear the lap records.
Stopwatch Glossary
- Stopwatch
- A specialized timepiece designed to measure the amount of time elapsed from a particular time when it is activated to the time when it is deactivated.
- Lap Time
- The total time recorded from the very beginning of the measurement up to a specific point (e.g., completing one lap of a track).
- Split Time
- The duration of time taken between the previous lap and the current lap. This is useful for analyzing pace consistency across different segments.
- Fullscreen Mode
- A viewing mode that expands the timer to fill the entire screen, hiding the browser interface, menus, and advertisements for maximum visibility.
- Wake Lock API
- A web browser feature that prevents the device's screen from dimming or locking automatically while an activity (like a running timer) is in progress.
Frequently Asked Questions
- Q.Is the timer accurate if I switch tabs or minimize the browser?
- Yes, it is highly accurate. The tool calculates the difference between the absolute start time and the current time, so even if background rendering pauses, the correct elapsed time will appear instantly when you return.
- Q.Will my screen go to sleep while timing?
- This tool uses the Wake Lock API to prevent your device screen from sleeping or dimming while the stopwatch is running (on supported browsers).
- Q.Are my lap times saved to a server?
- No. All processing is done entirely within your local browser environment. No data is ever sent to or stored on an external server.
- Q.What is the maximum time I can measure?
- There is no strict system limit (you can measure for days). However, please note that refreshing or closing the browser tab will reset your data.
- Q.Does it work offline?
- Yes. Once the page is fully loaded, the stopwatch will continue to function perfectly even if your device loses its internet connection.
Stopwatch Use Cases
Study & Exam Prep
Time yourself while taking practice exams or use the fullscreen mode as a prominent desk clock to manage your focus periods.
Sports & Training
Keep track of rest intervals during workouts, or measure lap times accurately while jogging or running sprints.
Presentation Rehearsals
Log laps for each slide or section to see where you are spending too much time and adjust your pacing accordingly.
Cooking & Routines
Precisely measure boiling times for recipes or track your daily routine tasks to find opportunities for better efficiency.
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