Stopwatch Online

How this online stopwatch works

Press Start and the display begins counting up immediately, in the format minutes:seconds.hundredths (or hours:minutes:seconds.hundredths once you pass sixty minutes). Press Pause at any point to freeze the display without losing your progress, then press Resume to continue exactly where you left off. Reset clears the elapsed time and any recorded laps back to zero, ready for a fresh run.

While the stopwatch is running, the Lap button becomes active. Each press records two numbers: the split (the time since your previous lap, or since Start if it is your first lap) and the total (the full elapsed time since you pressed Start). Both are added as a new row at the top of the lap list, so your most recent lap is always the first one you see without scrolling. You can record as many laps as you like in a single run; the list scrolls internally once it grows past a handful of rows.

The display updates roughly thirty times per second, which is smooth enough to read comfortably while still being light on your device's battery and CPU. The underlying elapsed time itself is calculated from your device's own clock each time the display refreshes, not by counting ticks, so switching to another browser tab and back never causes the displayed time to drift: it always reflects exactly how much real time has passed.

Reading your lap times

Once you have recorded two or more laps, the list highlights your fastest lap in green and your slowest lap in red, based on each lap's individual split time (not its running total). This makes it easy to see at a glance whether you sped up or slowed down over a run, without doing the subtraction yourself for every row.

A worked example: if you press Lap at 0:45.00, again at 1:32.50, and again at 2:10.00, your lap list shows Lap 1 with a 0:45.00 split and a 0:45.00 total, Lap 2 with a 0:47.50 split and a 1:32.50 total, and Lap 3 with a 0:37.50 split and a 2:10.00 total. Lap 3 would be highlighted as the fastest and Lap 2 as the slowest.

Common ways people use an online stopwatch

A stopwatch is one of the simplest tools on the web, which is exactly why it gets used for so many different things:

• Timing a workout, a set of intervals, or how long a warm-up takes.
• Running a classroom activity, a timed quiz, or a presentation rehearsal where you need to know exactly how long each section takes.
• Cooking or baking steps that a kitchen timer alone does not track well, especially when you want to compare how long each step actually took.
• Board games and tabletop timing, where a visible, large display works better than a phone's lock screen.
• Speedrunning any physical or mental task (a puzzle, a lap of a track, a practice presentation) where lap times reveal whether you are getting faster or slower over repeated attempts.
• Simple productivity tracking: starting the stopwatch when you begin a focused task and checking the total when you finish, without any account or app to set up first.

Fullscreen mode

The fullscreen button expands the display to fill your entire screen, with the digits scaling up dramatically so the elapsed time is readable from several meters away. This is especially useful in a classroom, at the front of a gym, or projected onto a screen during a group activity. On most browsers this uses the real Fullscreen API, which also hides the browser's own address bar and tab strip. On iOS Safari, which does not support fullscreen for an individual element, the stopwatch instead expands to fill the visible browser window using the same large-digit layout: press the fullscreen button again, or press Escape, to return to the normal view.

Stopwatch vs. countdown timer

A stopwatch counts up from zero with no defined end point: you decide when to stop it, and it measures how much time has passed. A countdown timer works the opposite way: you set a target duration and it counts down to zero, then alerts you. If you are looking for a duration that counts down and rings an alarm instead of an elapsed-time count-up display, see our full stopwatch vs. timer comparison for the difference and a pointer to a countdown timer.

Keyboard shortcuts

Once the page has loaded, you can control the stopwatch without touching the mouse: press Space to start or pause, L to record a lap while it is running, and R to reset. These only respond when you are not typing in a text field elsewhere on the page, so they never interfere with, for example, typing in the feedback form at the bottom of this page.

How accurate is a browser-based stopwatch?

This stopwatch reads your device's own system clock every time it refreshes the display, so the elapsed time it reports is accurate to well within a hundredth of a second under normal conditions. Two things are worth knowing if you need precision timing for something competitive or scientific:

• Background tabs are throttled by design. Modern browsers slow down JavaScript timers in a tab you are not looking at, to save battery. This stopwatch is built to tolerate that: because it recalculates the elapsed time from the clock rather than by counting ticks, switching away and back never causes drift, it just means the display briefly stops visually updating until you return to the tab. The underlying time is still exact.
• Human reaction time dominates manual lap-taking. Whatever tool you use, pressing a button to mark a lap or a finish always carries roughly 100-250 milliseconds of human reaction delay. For anything requiring true photo-finish precision (competitive racing, scientific measurement), a purpose-built timing system with a sensor is the right tool, not a manually-triggered stopwatch of any kind.

A few worked examples

Three concrete scenarios, walked through step by step, to show how the same start/lap/reset pattern applies everywhere:

• Practicing a five-minute presentation. Press Start when you begin speaking, and Lap at the end of each section (introduction, main point one, main point two, conclusion). If your introduction lap reads 1:40 and your target was one minute, you immediately know that section is running long, without waiting until the very end to find out your whole talk overshot.
• Comparing three attempts at the same task. Reset between each full attempt, then compare the final total each time. Three totals of 4:12, 3:58, and 4:05 tell you your second attempt was your best one, a pattern that would be easy to lose track of without writing each number down separately.
• Timing a recipe with multiple steps. Start when you begin, and press Lap at the end of each step (chopping, sauteing, simmering) instead of restarting the stopwatch for every step. The total column always shows how far into the whole recipe you are, while the split column shows exactly how long the step you just finished took, useful for adjusting your estimate for the next time you cook the same dish.

Works on any device, no install

This stopwatch runs in any modern desktop or mobile browser (Chrome, Firefox, Safari, Edge) with no app to install and no account to create. Bookmark the page if you use it often, or add it to your phone's home screen through your browser's own "Add to Home Screen" option for a one-tap launch that looks and feels like a regular app icon, while still just being this same web page underneath.

Your data and privacy

This stopwatch runs entirely on your own device using JavaScript. Your elapsed time, your laps, and how many times you have opened this page are never sent to a server or stored in a database anywhere. Closing or reloading the page clears everything. See the privacy policy for full details, including what a small, optional analytics beacon does and does not collect.

What this stopwatch does not do

To be upfront about scope: this is a single, general-purpose count-up stopwatch with laps. It deliberately does not include a few features some visitors search for, because they belong to genuinely different tools rather than being small additions to this one: an interval or round timer with configurable work/rest periods (tabata, HIIT, EMOM-style training), multiple simultaneous stopwatches running independently on one screen, a chess clock with two independent countdowns, and a speedcubing timer with a scramble generator and inspection countdown. If you were looking for any of those, they are worth searching for by name; this page is built specifically for the simpler, far more common case of one stopwatch, one running total, and a clean lap list.