Online stopwatch
Press Start, then Lap to mark each split. Space starts and stops, L records a lap.
Runs in your browser. Your times stay on this device.
0:00.00
Ready
Laps
| Lap | Lap time | Total |
|---|
How to use it
Start begins timing and turns into Stop. Lap records the time so far without stopping the clock, for each lap of a track, each round of a quiz or each step of a task. Reset clears the time and the laps once the stopwatch is stopped. On a keyboard, the Space bar starts and stops and the L key records a lap, so you can keep your eyes on what you are timing.
The time shows hundredths of a second, and hours appear once it passes 59 minutes 59 seconds. Full screen fills the screen with the time for a class or a gym; on phones that can't go full screen, it shows a big clock over the page instead.
Reading the lap table
Each row shows the lap time (how long that lap took) and the total (the time on the clock when you pressed Lap). Once there are three or more laps, the fastest is highlighted and the slowest shown in red. For example, four laps pressed at 1:00.00, 2:05.00, 3:00.00 and 4:10.00 give these rows:
| Lap | Lap time | Total | |
|---|---|---|---|
| 1 | 1:00.00 | 1:00.00 | |
| 2 | 1:05.00 | 2:05.00 | |
| 3 | 0:55.00 | 3:00.00 | Fastest |
| 4 | 1:10.00 | 4:10.00 | Slowest |
The lap time is the difference between two totals: lap 3 ended at 3:00.00 and lap 2 at 2:05.00, so lap 3 took 55 seconds. Copy times copies the total and every lap as plain text, ready to paste into a message or a spreadsheet.
Why it keeps the right time
The stopwatch notes the moment you press Start and works out the time from the clock, instead of counting ticks. That means it stays right when you switch tabs, when the phone dims the screen, or even when you close the tab: the running time and the laps are kept in this browser, so opening the page again picks up where it left off. While it runs, the page also asks the browser to keep the screen on, where the browser allows it.
Questions
How accurate is it?
The time comes from your device's clock, which is accurate to well under a hundredth of a second over a typical session. The biggest error is reaction time: a person pressing a button is usually a tenth of a second or more late, so for races that matter, use the same person to start and stop.
What is the difference between a stopwatch and a timer?
A stopwatch counts up from zero to measure how long something takes. A timer counts down from a set time and sounds an alarm at zero. For cooking, a Pomodoro session or a timed test, use the countdown timer.
Are my times saved anywhere?
Only in this browser on this device, so the stopwatch can carry on if you close the tab. Nothing is sent to a server. Reset clears them.