Summary: A Free Online Stopwatch with Lap Times
An online stopwatch is a timer that counts up from zero in your browser. This one shows minutes, seconds and hundredths (00:00.00) and switches to hours after 59:59.99. Click Start or press the Space bar, click Lap or press L each time a lap ends, and click Stop to pause; Resume carries on from the same time. Every lap gets a lap time and a split time, the fastest and slowest laps are colored, and Export CSV saves them as a file.
It is free, needs no sign-up and runs in your browser; nothing is uploaded (you can check the Network tab in DevTools). Times live only on the page. Reloading or closing the tab clears them, so export the laps first if you want to keep them.
Table of Use: Timing Jobs and Results
| What you are timing | What to press | What you get |
|---|---|---|
| Running or swimming laps | Click Start, then Lap each time you pass the line | Lap time and split for every lap, with the fastest and slowest highlighted |
| Interval training | Press L at every switch between work and rest | The length of each interval in the Lap Time column |
| Pendulum swings or reaction tests | Lap on each swing or trial, then Export CSV | A lap_times.csv file with seconds to three decimals for a spreadsheet |
| Speeches and presentations | Lap at the end of each section | Time spent per section and the running total |
| A big display for a classroom or gym | Click the fullscreen button | Very large digits and the latest lap underneath; Esc exits |
| Timing a long task | Start, Stop to pause and Resume to continue | One running total; hours appear after 59:59.99 |
| Lap | Split (total so far) | Lap time (split minus previous split) |
|---|---|---|
| Lap 1 | 00:31.20 | 00:31.20 (Fastest) |
| Lap 2 | 01:04.85 | 00:33.65 |
| Lap 3 | 01:40.10 | 00:35.25 (Slowest) |
Features of the Online Stopwatch
- Hundredths of a second. The time comes from the browser's monotonic clock, so a system clock change cannot make it jump.
- Unlimited laps. The Lap Times list shows the newest first, with lap time and split for each. Lap times are whole milliseconds, so they always add up exactly to the split.
- Fastest and slowest. Green and red rows appear from the second lap on.
- CSV export. The file lap_times.csv has the columns Lap, Lap Time, Split Time, Lap Time (s) and Split Time (s).
- Fullscreen view. The digits scale to the screen width and the latest lap is shown below them.
- Keyboard shortcuts. Space, L and R work without clicking, unless a text field, link or other control has focus, and can be switched off.
- Accessible controls. The time is exposed as a timer element, and focus moves to a working button when Lap or Reset becomes disabled.
It has no countdown, alarm or saved history. For counting down, use the Countdown Timer.
How to Use the Stopwatch
- Click Start (or press Space) at the moment the event begins.
- Click Lap (or press L) each time a lap, split or interval ends. Lap is disabled while the stopwatch is stopped.
- Click Stop to pause. The button turns into Resume, which continues from the same time.
- Read the Lap Times table below the clock, and click Export CSV to download it.
- Click Reset (or press R) to return to 00:00.00 and clear all laps.
- Use the fullscreen button for a large display, and Esc to leave it.
The exported CSV opens in any spreadsheet, or the CSV to JSON Converter can turn it into data for a script. To compare a start time with another city's clock, use the World Clock, and to turn a recorded Unix time into a date, the Timestamp Converter. For spans longer than a day, the Date Difference Calculator is the better fit.
Who Can Use the Stopwatch
- Runners, swimmers and coaches who want split times without a sports watch.
- Teachers and students running timed experiments and exporting the data.
- Speakers rehearsing a talk; paste the script into the Word Counter to compare words with minutes.
- Home cooks, gamers and anyone who needs elapsed time on a screen.
After timing a known distance, the Speed Calculator gives your average speed, and the Length Converter switches a 400 m track lap into miles or kilometers.
FAQs: Online Stopwatch Questions
What are the keyboard shortcuts for the online stopwatch?
Press Space to start, stop and resume, L to record a lap while the stopwatch is running, and R to reset the time to zero and clear the laps. They are on by default and can be switched off with the Keyboard shortcuts checkbox under the buttons; the stopwatch remembers that choice in this browser.
Why are the stopwatch keyboard shortcuts not working?
The keys are ignored while you type in a text field, when Ctrl, Alt or Command is held, or when focus is on a link or button elsewhere on the page. Space still presses a focused button such as Export CSV. Also check that the Keyboard shortcuts box is ticked. While it is ticked, Space starts the stopwatch instead of scrolling the page.
What is the difference between lap time and split time?
Lap time is how long one lap took: the time since the previous lap was recorded, or since the start for lap 1. Split time is the total elapsed time on the stopwatch at the moment you pressed Lap. Each lap time equals its split minus the previous split, so the laps always add up to the latest split.
How accurate is this online stopwatch?
It reads the browser's high-resolution monotonic clock (performance.now) and displays hundredths of a second, so the count does not drift and is unaffected if the computer's clock is adjusted mid-run. In practice the limit is your reaction time when pressing the buttons, which is far larger than 0.01 seconds.
Does the stopwatch keep running in a background tab or when my phone locks?
In a background tab, yes: the display stops refreshing, but the elapsed time is recalculated from the clock when you return. A phone or computer that goes to sleep is different, because the stopwatch does not request a screen wake lock and browsers may not count sleeping time. Keep the screen awake for long timings. Reloading or closing the tab resets the stopwatch.
How do I save lap times to Excel or Google Sheets?
Record at least one lap, then click Export CSV. The browser downloads lap_times.csv with one row per lap: lap number, lap time and split time as mm:ss.cc, plus both as plain seconds with three decimals. Open it in Excel, Google Sheets or Numbers; the seconds columns can be summed or charted directly. The file is created in your browser.
What do the green and red lap rows mean?
Once you have two or more laps, the quickest lap is highlighted green and labeled Fastest, and the slowest is highlighted red and labeled Slowest. The comparison uses lap time, not split time. If two laps tie for fastest, both are marked Fastest.
Is the online stopwatch free, and does it upload my times?
It is free, needs no sign-up and runs in your browser; nothing is uploaded, which you can confirm in the Network tab of DevTools. Lap times exist only on the page until you export them. The one thing remembered between visits is whether the Keyboard shortcuts box is ticked, kept in this browser's local storage.