Online Stopwatch and Timer
Start, lap, reset, or count down instead.
Runs entirely in your browser
Loading the tool…
00:00.00
Laps
- 0Laps
- —Fastest
- —Slowest
- —Average
| Lap | Split | Total |
|---|
The stopwatch is driven by the browser's monotonic clock, so it stays accurate even if the system clock changes underneath it, and it does not drift when the tab is backgrounded. Lap times record each split alongside the running total, with the fastest and slowest laps marked.
Switch to countdown mode for intervals like workouts, brewing or presentations, and the page beeps when it reaches zero.
Counting down to a day rather than a duration, a birthday or a deadline months out, is what the countdown to a date page is for.
How to use it
- Press Start. Press Lap to record a split without stopping the clock.
- Press Stop to pause, then Start again to continue, or Reset to clear.
- Switch to Countdown, enter a duration, and press Start to run it down to zero.
Questions
How accurate is a browser stopwatch?
Displayed to a hundredth of a second, and accurate to a few milliseconds, because it reads a monotonic clock rather than counting frames. It is not a substitute for certified race timing.
Does it keep running in a background tab?
The elapsed time stays correct because it is computed from timestamps, not by counting ticks, but browsers throttle background rendering so the display may only catch up when you return to the tab.
What does the lap list show?
Each row is one lap: the split for that lap and the total elapsed at the moment you pressed Lap, with the fastest and slowest laps highlighted.
Your data stays on your device
Everything above runs inside your browser as WebAssembly compiled from Rust. Nothing you type is uploaded, logged or stored on a server. There is no server. You can load this page once, go offline, and it still works.