Stopwatch
Free online stopwatch with lap times, hundredths of a second and full screen. It keeps exact time in a background tab and even after you reload the page.
Shortcuts: Space starts and pauses, L records a lap, R resets.
What it does
A stopwatch that measures elapsed time to the hundredth of a second, with a lap button that records each split and marks the fastest and the slowest. The time is calculated from the moment you pressed start, not counted tick by tick, so it stays exact when the tab is in the background, when the screen is locked, and even if you close the page and open it again in the same browser.
How to use it
- Press Start, or the Space bar.
- Press Lap, or the L key, at each split; the table shows the lap time and the running total.
- Pause to stop the clock, and Reset to start again. Copy the laps to paste them into a spreadsheet.
Frequently asked questions
Does it keep counting if I switch tabs or lock the screen?
Yes. The stopwatch stores the moment it started and calculates the elapsed time from the device clock whenever it is shown, so a background tab or a locked screen does not slow it down. It even survives closing the page: open it again in the same browser and the time is still running.
How precise is it?
It shows hundredths of a second and reads the device clock, which is accurate to the millisecond. In practice the limit is your reaction time when pressing the button, which is around two tenths of a second for most people.
What do fastest and slowest mean in the lap table?
Once there are at least two laps, the shortest lap time is marked as the fastest and the longest as the slowest, so you can see your best and worst split at a glance.
Can I save my lap times?
Yes. Copy laps puts the table on the clipboard as text separated by tabs, ready to paste into a spreadsheet or a message. The current session is also kept in this browser until you press Reset.