Stopwatch
Time anything with laps down to the hundredth.
Space to start or pause, L for a lap, R to reset.
| Lap | Split | Total |
|---|
- Hundredths of a second
- Fastest and slowest laps highlighted
- Export laps as CSV
How to use the stopwatch
- Click Start, or press the space bar.
- Click Lap to record a split without stopping the clock.
- Click Reset when you are done, or export your laps as CSV.
Split time versus total time
| Lap | Split | Total |
|---|---|---|
| 1 | 1:32.10 | 1:32.10 |
| 2 | 1:28.44 | 3:00.54 |
| 3 | 1:35.02 | 4:35.56 |
Split is how long that one lap took by itself. Total keeps adding up from the moment you pressed Start, which is why it always grows, even on a slower lap.
What people use a stopwatch for
- Timing running, swimming or cycling intervals, with laps marking each repeat.
- Cooking steps that need a precise time rather than a rough countdown, like resting dough or simmering a sauce.
- Practicing a speech or presentation to see if it fits its time slot.
- Simple time tracking for a task or a work session when you want a running total rather than a fixed countdown.
Reading the fastest and slowest highlights
Once you have a few laps recorded, the quickest split is marked in green and the slowest in red. This makes it easy to spot pacing problems, like a strong start that fades, or a warm-up lap that was much slower than the rest, without doing the comparison yourself.
Stopwatch versus a countdown timer
A stopwatch counts up from zero with no end point, which suits anything where you want to measure how long something actually takes. A countdown timer, like the online timer, counts down to zero from a length you set in advance, which suits anything with a fixed time limit.
If you are not sure how long a task will take, start with the stopwatch. Once you know roughly how long it needs, switch to a countdown for future attempts so you have a clear target to beat.
Stopwatch FAQ
How accurate is this stopwatch?
It reads elapsed time from your device's high-resolution clock and displays it to the hundredth of a second, accurate enough for training, cooking and most timing needs.
What is the difference between split and total?
Split is the time since your last lap. Total is the time since you pressed Start, which keeps adding up across every lap.
How are the fastest and slowest laps marked?
The quickest split is highlighted in green and the slowest in red, so you can spot your best and worst laps at a glance.
Can I keep a record of my laps?
Yes, click export CSV to download your lap and total times as a spreadsheet file.
What keyboard shortcuts does it support?
Space starts or pauses, L records a lap, and R resets, so you can run it hands-free once you know the keys, useful mid-workout when reaching for a mouse is awkward.
Why use performance.now() instead of a regular clock?
It reads a high-resolution, monotonic timer built into the browser that never jumps backward or forward the way a device's wall clock can, for example around a daylight saving change, which keeps lap and total times reliable.
Can I track running splits with this?
Yes. Tap Lap at the end of each mile or interval, and both the split time for that segment and the running total are recorded, similar to a runner's watch.
What can I do with the exported CSV file?
Open it in a spreadsheet app like Excel, Google Sheets or Numbers to chart your lap times, compare sessions, or keep a training log over time.