Stopwatch

How to use the stopwatch

1. Press Start or the spacebar. The digits count up in hundredths of a second.
2. Press Lap or L to record a lap. It appears in the table with its lap time and the total.
3. Press Stop or the spacebar to pause. Resume carries on from the same time.
4. Press Copy CSV or Download CSV to take your laps to a spreadsheet.
5. Press Reset or R to start over. Reset by mistake? Press Undo within 8 seconds.

It works in any modern browser on a phone, tablet or computer, with nothing to install.

What people time with it

• Track, pool and running laps. A coach presses Lap each time a runner passes and copies the splits into a training log afterwards.
• Lab practicals and time studies. Record each repetition of a task, then average the millisecond columns in a spreadsheet.
• Rooms, gyms and streams. Put the digits on a TV or projector so everyone sees how long a plank, a game round or a demo has run.
• Study and focus sessions. Count up your focus time with a calm theme. For fixed blocks with breaks, use the Pomodoro-style timer, or keep an aesthetic clock on screen.

Laps and splits explained

A lap is the time since the previous lap. A split is the total time since you pressed Start; the table calls it Total. Press Lap at 25.22, 50.24 and 62.34 seconds and your laps are 25.22, 25.02 and 12.10 seconds. From three laps on, the quickest and the longest lap get the labels Fastest and Slowest, and the line above the table adds the average.

Pressing Stop doesn’t create a lap. The time since your last lap stays in the grey Current lap row and is exported as an end row. One run holds up to 999 laps.

Copy lap times into a spreadsheet

Press Copy CSV, click cell A1 in your spreadsheet and paste. The laps fill five columns: lap, lap time, total time, lap in milliseconds and total in milliseconds. The two millisecond columns are plain numbers, so formulas for averages or differences work right away. Download CSV saves the same table as a file named after the date and time, such as stopwatch-laps-2026-11-05-2305.csv. Exports always use hundredths, whatever the display shows.

A full screen stopwatch for rooms, gyms and streams

Press Fullscreen, press F, or double-click the digits on a computer. The digits fill the screen, the last three laps appear underneath, and the buttons fade until you move the mouse or tap. Where the browser supports it, the screen stays on while the stopwatch runs. Safari on iPhone can’t show a web page in true fullscreen, so the stopwatch fills the window instead; for real fullscreen, use Share → Add to Home Screen, where the screen stays on from iOS 18.4.

A stopwatch overlay for streaming software

Choose Share → Copy OBS link and add it as a browser source in your streaming software. The background is transparent and only the digits show. Add autostart=1 to start counting when the source loads and laps=1 to show the last three laps.

Keyboard shortcuts

Use the spacebar to start and stop the stopwatch without looking.

Options explained

• Precision: 1/100 s (default), 1/10 s or 1 s for the big digits; exports keep hundredths.
• Show last 3 laps in fullscreen: on by default.
• Click sound on lap: a short click for each lap, off by default; the Sound button and M switch it too.
• Volume (70 % by default), Keep screen on and Show time in tab title, which shows “12:34 · Stopwatch” in the tab.
• Theme: Auto follows the site; Night, Day, High contrast, Ocean, Dusk and Forest are the others.
• Announce every minute: screen readers hear “5 minutes” each minute; off by default.
• Clear my data: deletes the saved stopwatch and settings from this browser.

How this stopwatch keeps accurate time

This digital stopwatch runs in your browser. When you press Start, it saves that moment from your device clock, and every screen update shows the current time minus that moment. It never adds up ticks, so a busy computer or a background tab can’t make it drift. Laps are stamped with the moment of your key press or tap as the browser recorded it, not when the page got around to it. Because the start moment is saved on your device, the stopwatch keeps counting through a closed tab, a reload or a sleeping laptop, and shows the right time when you return. More detail: how our timers stay accurate.

Why hundredths, not milliseconds?

The stopwatch measures time to about a millisecond, but a typical screen redraws only every 16.7 ms, so a millisecond digit would be a blur. Your reaction time and the delay between your finger and the browser are longer than a hundredth anyway. Stopped times are cut off at the hundredth, never rounded up.

Tips and limits

• The stopwatch is saved in this browser only, so it doesn’t follow you to another device.
• Private windows forget it when they close, and clearing site data resets it.
• If the device clock jumps forward during a run, the jump is added; a jump backward is ignored.
• For runs of several hours, choose 1/10 s and lower the brightness to save battery.
• Some in-app browsers block downloads; use Copy CSV there.

OBS Studio, Excel, Google Sheets and Numbers are trademarks of their owners; HugeTimer is not affiliated with them.

Updated November 6, 2026