Stopwatch
A big, clean online stopwatch. Start, pause, log laps, or reset. Millisecond precision, zero signup.
How this stopwatch works
We use performance.now() for high-precision timing and requestAnimationFrame for smooth display updates. Unlike interval-based timers, the accumulated time is always correct — even if you switch browser tabs, because the math runs on real timestamps, not frame counts.
What to use it for
Time yourself cooking pasta, measure a 40-yard dash, track how long you focus before checking phone again, or settle a bet. Click Lap mid-run to mark a split — every lap is appended to a list below.
Frequently asked questions
How precise is this?
The display shows milliseconds. Browser tab throttling keeps actual accuracy in the ±20 ms range, which is plenty for cooking, sports training, and everyday use.
Will it keep running in the background?
Yes — elapsed time is calculated from real wall-clock timestamps, not frame counts. When you return to the tab the display catches up instantly.
How do I record split times?
Click <strong>Lap</strong> while running. Each entry shows the cumulative time at that click.
Does it work on my phone?
Fully responsive, big buttons for fat fingers. Add to home screen for one-tap access.
Why does the display sometimes stutter?
When the tab is backgrounded or the machine is under load, Chrome throttles rAF. Timing itself is never affected — only how often the screen refreshes.
Last updated
For general calculations only. Not financial, tax, or legal advice — see our disclaimer.