A precise stopwatch in your browser
This free online stopwatch measures time to the hundredth of a second, records lap times and can beep at regular intervals. It runs on any computer, tablet or phone, with no app and no sign-up. Coaches, runners, swimmers, teachers, students, cooks and anyone curious about how long something really takes can put it to work.
The time is read from your device clock, so it stays exact even if you switch to another tab or the browser slows the page down. Come back later and the stopwatch shows the right time, still running.
How to use the stopwatch
Start, pause and reset
Press Start and the digits begin to run, down to the hundredths. Press Pause to freeze the time and read it calmly; Resume carries on from there. Reset brings everything back to zero.
Record laps
Press Lap while the stopwatch runs to save a lap without stopping the clock. Each lap shows two times: its own duration and the total time since the start. Here is what four laps of a quarter-mile track can look like:
| Lap | Lap time | Total |
|---|---|---|
| 1 | 1:52.40 | 1:52.40 |
| 2 | 1:55.10 | 3:47.50 |
| 3 | 1:54.75 | 5:42.25 |
| 4 | 1:49.30 | 7:31.55 |
Lap times show your pacing at a glance; the last total is your final time.
Add a regular beep
Turn on an optional beep every 30 seconds, every minute or every 5 minutes, using the sound of your choice. It is perfect for intervals, for pacing a run without looking at the screen or for keeping a speech on track.
Full screen and focus mode
Press the full screen button to fill the screen with the time. A small bar appears when you move the mouse or touch the screen, with buttons to change the size or leave full screen. While the stopwatch runs, the settings fade away after a few seconds so only the time remains; a touch brings them back.
Two styles: Classic and Coach
Classic
Big, clear digits that fill the screen, readable from across a gym or a classroom.
Coach
A round, old-school stopwatch like the ones coaches used to wear around their necks. The crown on top starts and stops the time, and the side pusher records laps and resets. Small labels next to each button tell you what it will do, so there is no guessing.
Both styles offer the same laps, beeps, colors and full screen mode, and your choice of style is remembered in your browser.
What you can time
- Running and swimming: laps on a track or lengths in a pool, with a total at the end.
- Gym and home workouts: how long you hold a plank, rests between sets, circuits with a beep every 30 seconds. For a ready-made routine, try the 7 minute timer.
- School: reading speed, timed math facts, science experiments and races at recess.
- Work: how long a task really takes, a talk rehearsal or a meeting.
- Kitchen: how long the dough has been rising or the sauce has been simmering.
- Science class: time ten swings of a pendulum and divide by ten for a more accurate result than a single swing.
- Public speaking: rehearse a talk and press Lap at the end of each part to see where the time goes.
- Games: speed puzzles, puzzle cube solves and trivia rounds.
To count down instead of up, use the online timer, or a ready-made one like the 1 minute timer.
Tips for accurate timing
- Mind your reaction time. People take around two tenths of a second to react. Start and stop on the same kind of signal, both on sight or both on a sound, so the delays tend to cancel out.
- Use Lap instead of stopping. Stopping and restarting adds a small error each time; laps keep one continuous time.
- Keep the tab open. You can switch tabs freely, but closing this one stops the stopwatch.
- Go full screen and use the size buttons for a display that everyone can read.
- Write down important laps before you press Reset.
- Name your laps on paper as you go, such as warm-up, main set and cooldown, so the times still make sense later.
Interval training with the beep
The regular beep turns the stopwatch into a simple interval timer, while the main display keeps counting the total time of your session.
- Every minute on the minute: set the beep to every minute, do a set of an exercise at each beep and rest for what remains of the minute.
- 30-second intervals: alternate 30 seconds of work and 30 seconds of rest, or switch exercises at each beep.
- Long runs and rides: a beep every 5 minutes reminds you to drink, check your pace or change position.
A short history of the stopwatch
In 1816, the French watchmaker Louis Moinet built an instrument for astronomy that counted sixtieths of a second. It is often called the first chronograph. A few years later, in 1821, Nicolas Rieussec built a timer for horse races in Paris that marked the time with drops of ink on a turning dial. That is where the word chronograph, “time writer”, comes from.
Push-button stopwatches spread in the late 19th century, and in 1916 the Swiss maker Heuer released a mechanical stopwatch that could measure a hundredth of a second. Since the 1970s, top athletics events have used fully automatic electronic timing, and results are still given to the hundredth: in a 100 meter final, a few hundredths of a second can separate gold from silver. This online stopwatch puts the same level of detail on your screen.
Online stopwatch, phone or handheld?
A handheld stopwatch is tough and has real buttons, but it is small and only one person can read it. A phone stopwatch is always in your pocket, but its digits are tiny and notifications get in the way. An online stopwatch turns a laptop, a tablet or a projector into a big shared display, for free, so a whole team or class can follow the same time. Pair it with the full screen clock to show the time of day, or with the Pomodoro timer to structure work sessions.
Private and easy to use
There is no account and nothing is sent to a server: your style, color and beep settings are saved in your own browser. Once loaded, the stopwatch works offline. While it runs, the controls fade away after a few seconds; a touch or a mouse move brings them back. The page also asks the screen to stay on while the stopwatch runs, on devices that allow it.