Online stopwatch
Start, lap, stop. Tenths of a second, lap and split times, and it keeps counting even if you close the tab.
Space start/stop · L lap · R reset · F full screen
Laps (0)
Press Lap while running to record lap and split times. The sweep on the dial marks each minute.
Lap time vs split time
A lap time is how long one lap took on its own. A split is the running total when you hit the button. Runners use lap times to check pace consistency and splits to check they’re on schedule for a finish time. Both are recorded here, and the list can be copied as a table into a spreadsheet.
Need to count down instead of up? Use the countdown timer, or the interval timer for repeats.
Questions
How accurate is this online stopwatch?
It measures elapsed time from the browser’s clock, so it doesn’t lose time in a background tab. The display shows tenths of a second; real precision is limited by how fast you tap, since human reaction time is typically around 0.2 seconds.
Does the stopwatch keep running if I close the tab?
The start time is saved in your browser, so if you close and reopen the page the stopwatch picks up with the correct elapsed time, as if it had kept running.
How do laps and splits work?
Press Lap to record the time since the previous lap (the lap time) and the total so far (the split). Your fastest and slowest laps are highlighted.
Are there keyboard shortcuts?
Space starts and stops, L records a lap, and R resets when stopped.