Online Stopwatch
A precise fullscreen stopwatch with start, stop, reset and lap times you can review.
Quick answer
What is the Online Stopwatch?
An online stopwatch measures elapsed time from start to stop, to the hundredth of a second, in big fullscreen digits. Record laps for running, swimming, workouts and experiments, and the time stays accurate because it is measured against your device clock.
Key features
- Start, stop, lap and reset
- Hundredths of a second precision
- Lap list with split times
- Space bar and keyboard shortcuts
Why use it
- Large display for gyms and classrooms
- Accurate lap timing
- Free, works offline
Built and tested by Whitson Rao
About the Online Stopwatch
A precise, fullscreen online stopwatch with lap times. Big digits, keyboard shortcuts, and accurate timing based on your device clock.
How accurate is a browser stopwatch?
The stopwatch counts from the system clock rather than adding up timer ticks, so it stays accurate to the hundredth of a second even if the tab is busy or in the background. What you see on screen is redrawn many times a second, but the time itself always comes from the difference between now and the moment you pressed Start.
For laps, each lap time is the gap since the previous lap, and the split is the total since Start. That makes it easy to compare intervals in training, cooking or presentations.
Good uses for a fullscreen stopwatch
A big, high-contrast display can be read from across a room, which suits classrooms, workshops, speed-cubing, timed exercises and live streams. Pair it with the Countdown Timer when you need a fixed limit, or the Pomodoro Timer for focus sessions with breaks.
How to use the Online Stopwatch
Press Start or Space to begin timing.
Press Lap or L to record a split while the stopwatch keeps running.
Press Space to pause, and R to reset.
Press F for fullscreen, and Esc to exit.
Common uses
Sports & running
Track lap times and intervals.
Speeches
Time talks and rehearsals precisely.
Games & quizzes
Time rounds in classrooms or game nights.
Lab and kitchen
Measure reactions, brewing or steeping times.
Frequently asked questions
How accurate is the stopwatch?
It uses the browser’s high-resolution clock and displays hundredths of a second. Display refresh can delay the visible update by a few milliseconds.
Are my laps saved?
Laps stay on the page until you reset or close it. You can copy them to the clipboard.
Does it work offline?
Yes. Once the page has loaded, the stopwatch runs without a connection.