Online stopwatch: millisecond precision, unlimited laps
A free online stopwatch and lap timer for your browser. High-resolution clock, fastest and slowest lap highlighting, CSV export. No sign-up, no ads blocking the stopwatch, works offline.
- Millisecond precision
- Unlimited laps + splits
- CSV export of every lap
- Keyboard shortcuts
- Works offline
Space start/pause · L lap · R reset
Ready when you are
Hit Start (or press Space). Tap Lap to record splits — the fastest and slowest laps are highlighted automatically, and you can export the full table as CSV.
Uses your device's high-resolution clock for millisecond accuracy. Laps are stored on your device only.
- 100% Free
- Millisecond Precision
- Unlimited Laps
- Fastest / Slowest
- CSV Export
- Works Offline
- No Sign-up
What is an online stopwatch?
An online stopwatch is a timer that counts up from zero in your browser, so you can measure how long anything takes without installing an app. This one reads your device's high-resolution clock, shows hours, minutes, seconds and milliseconds, and lets you record unlimited laps with split times.
Unlike a basic stopwatch that only shows one big number, it works as a full lap timer. Every lap shows the total time and the split since the previous lap, the fastest and slowest laps are highlighted for you, and the whole table can be downloaded as a CSV or copied as text. Your time and laps are kept in your browser, so a reload does not lose them.
If you need to count down instead of up, try the Countdown Timer, or use the Pomodoro Timer for focus sessions.
When precision matters, and when it does not
Milliseconds matter for some uses and are just noise for others. A quick guide.
| Use case | Precision needed | Export useful? |
|---|---|---|
| Running / sprint intervals | Milliseconds matter | Yes, compare across sessions |
| Swimming sets | Milliseconds matter | Yes, track pacing |
| Presentations / speeches | Seconds are enough | Rarely |
| Lab experiments | Milliseconds matter | Yes, for analysis |
| Coaching / refereeing | Tenths of a second | Yes, share with team |
| Everyday timing | Seconds are enough | Rarely |
Why this is the best free online stopwatch
Most free stopwatches are one big number. This one is a proper lap timer with export and stats.
| Feature | TToolDeck | Typical online stopwatches | Desktop stopwatch apps |
|---|---|---|---|
| No sign-up or email | Yes | Partial | No |
| No ads blocking the stopwatch | Yes | No | Yes |
| Millisecond precision (performance.now) | Yes | Partial | Yes |
| Unlimited laps with split times | Yes | Partial | Yes |
| Fastest and slowest lap highlighting | Yes | No | Partial |
| Keyboard shortcuts (Space, L, R) | Yes | Partial | Yes |
| Export laps as CSV | Yes | No | Partial |
| Copy laps to clipboard in one tap | Yes | No | No |
| Running time in the browser tab title | Yes | No | No |
| Persists across page reload | Yes | No | Partial |
| Works offline after first load | Yes | No | Yes |
| Nothing to install, works on any device | Yes | Yes | No |
| Free for personal, work and school use | Yes | Partial | Partial |
Comparison reflects publicly available information at the time of writing. Features may change. Representative examples of common patterns.
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How it works
- 1
Start the stopwatch
Hit Start (or press Space). The display runs with millisecond precision using your device's high-resolution clock.
- 2
Tap lap for each split
Press Lap (or press L) at any moment to record the current time. Each lap shows both the running total and the split since the last lap.
- 3
Export or copy when done
Fastest and slowest laps are highlighted automatically. Download the full table as a CSV, or copy it as text with one tap.
Stopwatch keyboard shortcuts
Keep your hands on the keyboard and your eyes on what you are timing.
| Key | Action | Notes |
|---|---|---|
| Space | Start or pause the stopwatch | Press again to resume from the same point |
| L | Record a lap | Adds a row with total time and split |
| R | Reset the stopwatch | Asks for confirmation before clearing laps |
Stopwatch, lap timer, countdown or Pomodoro?
Pick the right timer for the job.
| Tool | How it counts | Best for |
|---|---|---|
| Stopwatch | Counts up from zero | Measuring how long something takes |
| Lap timer | Counts up and records splits | Intervals, laps, trials and pacing |
| Countdown timer | Counts down to zero | Doing something for a fixed amount of time |
| Pomodoro timer | Repeating focus and break cycles | Study sessions and deep work |
Everything you get for free
Millisecond precision
The stopwatch reads from performance.now(), the browser's high-resolution monotonic clock. Unlike Date.now(), it is not affected by system clock changes, and it stays accurate even when the UI thread is busy or the tab is throttled.
Unlimited laps with splits
Tap Lap (or press L) at any moment and a row is added with the total elapsed and the split: the time since the previous lap. Run hundreds of laps; the table scrolls, stats stay live.
Fastest and slowest highlighted
The fastest lap gets a green row and a "FAST" badge; the slowest gets a red row and a "SLOW" badge. On a long training session or a series of trials, this saves scanning the whole table.
CSV export of every lap
One click downloads the full lap table as a CSV with lap number, split in milliseconds, total in milliseconds, and both times in human-readable form. Opens straight in Excel, Numbers or Google Sheets.
Copy laps to clipboard
Prefer to paste results into a doc or a message? One tap copies the whole table as tab-separated text. It pastes cleanly into any editor, spreadsheet or chat.
Live tab title
The browser tab shows the running time down to the millisecond, so you can keep the stopwatch open in the background and glance at the top of the window without switching back.
Keyboard shortcuts
Space starts and pauses. L records a lap. R resets and asks for confirmation. Perfect for timing presentations where you do not want to take your eyes off the room.
Persists across reload
Close the tab mid-session and reopen it. The current time and every recorded lap are exactly where you left them. State is stored in your browser only; nothing is synced to a server.
Works offline
After the first load, the stopwatch, lap recording and CSV export all run in your browser. Disconnect from the internet and it keeps timing, which is handy in gyms, pools, labs and classrooms with poor signal.
Mobile friendly
The layout is fully responsive and the Start, Pause, Lap and Reset buttons are large enough to tap accurately with a thumb on iPhone, Android and tablets. No app to install.
No ads, no sign-up
Nothing sits between you and the Start button. No account, no email, no pop-ups, no banner covering the clock. Open the page and start timing.
Free for any use
Personal, commercial and educational use are all free. Use it for training sessions, lab classes, client work or team events without limits or watermarks.
What people use it for
Running and sprint training
Time intervals on a track or treadmill, tap Lap at the end of each one, and see immediately which was fastest. Export the CSV to compare against previous sessions.
Swimming and pool sets
Time a series of 50m or 100m efforts with one lap each. The split column shows pacing, and the fastest/slowest highlighting makes it obvious where the pace dropped.
Presentations and speeches
Keep the stopwatch running on a second screen or on a phone and glance at the tab title. Space to pause if you are interrupted, Space again to resume from exactly where you were.
Physics and lab experiments
Millisecond precision and lap timing are exactly what you need for reaction-time tests, pendulum periods, or any experiment that requires recording multiple time intervals.
Coaching and refereeing
Time each athlete, each trial, each penalty. Export the CSV after the session and share with the team. No app install, works from the browser on any device.
Productivity experiments
How long does a task really take? Time it with lap markers for each stage (setup, execution, cleanup) and export the breakdown to see where the time went.
Gaming and speedruns
Record splits for each level, boss or checkpoint in a run. The split column shows where you gained or lost time, and the CSV lets you compare attempts side by side.
Study sessions and exams
Time how long each practice question or past-paper section takes. Lap after every question to find the ones that slow you down before the real exam.
Questions people ask
How do I use an online stopwatch?
Press Start (or tap the Space bar). The time runs continuously, showing hours, minutes, seconds and milliseconds. Press Lap (or L) to record a split. Each lap is added to a table below with its total and the delta from the previous lap. Press Pause to freeze the display, Resume to continue from the same point, or Reset to clear everything.
Is the stopwatch accurate?
Yes. The tool uses performance.now(), the browser's high-resolution monotonic clock, which is accurate to the millisecond. Unlike Date.now(), it is unaffected by system clock changes and stays precise even when the tab is in the background or the UI thread is busy. The display only updates once per animation frame, but the underlying time calculation is continuous.
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 to zero and alerts you when it ends. Use a stopwatch when you do not know the duration in advance, and a countdown timer when you want to stop at a fixed time. ToolDeck also has a Countdown Timer and a Pomodoro Timer for those jobs.
What is the difference between a lap and a split?
A lap is a recorded point in time: the moment you tapped Lap. A split is the interval between two laps: the time since the previous lap. The table shows both. The Total column is cumulative time from the start, and the Split column is the delta for that one lap. For interval training, splits matter more; for a total time at a specific checkpoint, laps do.
How do I record lap times on a stopwatch?
Start the stopwatch, then press the Lap button (or the L key) each time you complete a lap, interval or stage. The stopwatch keeps running, and each press adds a new row with the total time and the split. When you finish, download the table as a CSV or copy it as text.
How do fastest and slowest laps work?
The tool compares all splits (excluding lap 1, which has no previous reference) and highlights the smallest split in green with a "FAST" badge, and the largest split in red with a "SLOW" badge. This makes it easy to see pacing at a glance on a long training session.
Can I export the laps?
Yes. Click Download CSV to save the full lap table as a comma-separated file with lap number, split in milliseconds, total in milliseconds, and both times in a human-readable format. It opens directly in Excel, Numbers or Google Sheets. You can also click Copy to grab the whole table as tab-separated text for pasting into a doc or message.
What happens if I close the tab?
The current time and every recorded lap are saved to your browser's localStorage, so they survive a reload or a full close-and-reopen. When you come back, the stopwatch is paused but the elapsed time and lap table are exactly where you left them. Press Resume to keep going, or Reset to start fresh.
Can I keep the stopwatch running in the background?
Yes. The stopwatch uses performance.now() to compute elapsed time, so it stays accurate even when the tab is backgrounded or throttled. The tab title shows the live time, so you can glance at the top of your browser window without switching tabs.
Do the keyboard shortcuts work if the tab is not focused?
No. The Space, L and R shortcuts only fire when the stopwatch tab has focus. This is a browser and OS security restriction, not a limit of the tool. The stopwatch itself keeps running regardless of focus.
Is there a limit on the number of laps?
No. You can record hundreds of laps. The table scrolls and stays responsive. For very long sessions with thousands of laps, exporting to CSV keeps everything manageable.
Can I use it on a phone?
Yes. The layout is fully responsive, and the Start, Pause, Lap and Reset buttons are large enough to tap accurately with a thumb. It works in Safari on iPhone and Chrome on Android, and the tab title also works on mobile browsers, so you can leave the stopwatch open in the background.
Is it better than the stopwatch app on my phone?
It depends on the job. A phone app is fine for a quick time. This stopwatch adds millisecond precision, fastest and slowest lap highlighting, CSV export, copy-to-clipboard and keyboard shortcuts, and it works on a laptop or desktop with no install. It is a good choice when you want to analyse laps afterwards, not just read the clock.
Is it free, and can I use it at work or in a school?
Completely free for personal, commercial and educational use. No sign-up, no email, no ads blocking the stopwatch, no daily limit. Everything runs in your browser, and nothing from this page touches your data.
Does it work offline?
Yes. Once the page has loaded, the stopwatch, lap recording, CSV export and everything else run entirely client-side. You can disconnect the internet and it keeps working. Only the initial page load and fonts require a connection.
Your laps stay on your device
Lap times and elapsed time are stored in your browser's localStorage only. There is no account, no sync, no server. Clearing site data resets everything. See why ToolDeck is different.