How do I use the stopwatch?
Press Start to begin. Lap marks a point without stopping the clock. Stop ends the session.
Reset clears the time and all laps. The old list doesn't come back.
What do the lap numbers mean?
Each row has a lap time and a total split. The lap time counts from your last mark, the total split from when you first pressed Start.
Use laps for track rounds, swim lengths, talk sections, build steps, or any task with clear parts. The main clock keeps running while you add them.
How do I copy the lap list?
Press Copy laps. TimerBox copies the lap number, lap time, and total split as tab-separated text. Paste it into a spreadsheet or a plain text note.
The columns line up in Excel, Google Sheets, Numbers, and most other sheet tools, so there's nothing to screenshot or retype.
What can I time?
For a run or ride, press Lap at each set point. In a talk, mark the start of each section. A build splits neatly into build, test, review, and release.
The lap list turns one total into a simple record of each part. It can show where a session took more or less time than you expected.
What happens in a hidden tab?
The stopwatch ties the run to clock time, so when the page can run again it checks the clock and updates the display. A sleeping device can still pause the visible updates until it wakes.
This is a browser tool, not certified race or lab equipment. Use the proper timing gear when an official or safety-critical result matters.
Keyboard and fullscreen controls
Space starts and stops the watch. R resets it. Fullscreen puts the time and lap list in a large view for a second screen or projector.