Online Stopwatch
Centisecond-precise timing with laps
A stopwatch that reads hundredths and keeps a lap table. Start counts up from zero; pause freezes the display without losing what has accumulated, and pressing Start again resumes from where it stopped rather than from scratch. Each time you press Lap, the running total is recorded along with the interval since the previous lap, so a table shows two numbers per row — the split and the cumulative time — and flags the fastest and slowest splits once there is more than one. The clock itself is the browser's high-resolution timer, read through requestAnimationFrame on every frame, which is what makes the centisecond digits meaningful rather than decorative. Nothing is stored after you leave the page: no laps, no times, no account.
A precise online stopwatch with start, stop, lap and split timing that keeps running accurately in the background. No install, no ads shouting at you — just a clean timer.
Private Online Stopwatch In Your Browser
Online Stopwatch is processed locally with client-side JavaScript. Your files never touch a server, and there is no queue to wait in.
How to use Online Stopwatch
Press Start to begin counting; the display updates continuously from that moment.
Press Pause to freeze the reading, and Start again to resume from the same value.
Press Lap at each interval you want to record — a new row appears in the lap table with split and total.
Press Reset to stop the clock and clear both the display and the lap table.
- Timing is read from performance.now(), the browser's high-resolution monotonic clock, rather than the wall clock, so system time adjustments mid-run cannot corrupt a measurement.
- Display updates are driven by requestAnimationFrame, which keeps the centisecond digits in step with the screen's refresh.
- Lap rows record both the interval since the previous lap and the cumulative total, with the fastest and slowest splits labelled once there is more than one.
- Pause preserves the accumulated offset so resuming continues from the frozen value instead of restarting.
- A runner times their splits over a distance and compares them to find where the lap fell apart.
- A cook times a resting dough or a braise and compares consecutive attempts.
- A developer measures how long a build or test run actually takes on their machine.