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SmaftyTools

Stopwatch

Free online stopwatch with lap times and millisecond precision. Start, pause and reset — no install, works in any browser.

About Stopwatch

The Online Stopwatch measures elapsed time with centisecond (1/100 s) precision — start, pause, resume and reset with a single click or tap, and record unlimited laps that show both the individual split and the running cumulative total. As a browser-based lap timer it needs no installation, no account and no plugin; open the page on desktop, tablet or phone and it's ready to go, which is what makes it a genuinely useful free stopwatch with laps for anyone who just needs an accurate clock, not a fitness app.

That combination of precision and simplicity makes it useful well beyond a single use case. Coaches and athletes use it to time HIIT intervals, rest periods and swim laps; speedcubers use the lap feature to log solve-after-solve times during a practice session; home cooks use it for anything from a 3-minute egg to a 20-minute proof; teachers use it to keep classroom activities and timed tests on schedule; and meeting facilitators use it to keep agenda items from running long. Because laps are numbered and timestamped individually, it also works as a quick way to benchmark repeated tasks — comparing five attempts at the same drill, for example — without reaching for a spreadsheet.

Under the hood, the stopwatch is anchored to a start timestamp rather than counting screen-refresh ticks. Each time the display updates, it recalculates elapsed time as "now minus start timestamp" (adjusted for any paused intervals), so the count stays correct even when a browser throttles timers in a background or minimized tab — something a naive interval-based online stopwatch would drift on. Switch back to the tab and the display simply catches up to the correct value instantly, rather than needing to replay lost ticks.

One thing to keep in mind: the running time and lap list live only in the page's memory, so refreshing or closing the tab clears them — there's no cloud sync or saved history, by design, since nothing you do here ever leaves your browser. If you need a fixed count-down instead of a count-up, the companion Countdown Timer covers that case.

How to Use the Stopwatch

  1. Click Start to begin timing.
  2. Click Lap to record a split without stopping the clock.
  3. Use Pause and Resume as needed, and Reset to clear everything.

Features

  • Centisecond precision with a large, readable display
  • Unlimited laps with per-lap and cumulative times
  • Pause and resume without losing time
  • Accurate even when the tab is in the background

Examples

Timing interval sprints

Input

8 rounds, Lap pressed at the end of each round

Output

8 individual lap times plus a running cumulative total, e.g. Lap 1: 0:42.15, Lap 8: 5:58.30

Speedcubing practice session

Input

12 solves timed back-to-back, Lap pressed after each solve

Output

12 lap times listed in order (e.g. best 11.42s, worst 18.07s), ready to compare solve-to-solve

Cooking a multi-step recipe

Input

Start at prep, lap at "dough rests", lap at "oven preheated", stop at "done"

Output

3 lap splits recorded (e.g. 5:10, 12:45, 28:30) showing how long each stage took

Frequently Asked Questions

How accurate is the stopwatch?

It's anchored to your device's system clock, so total elapsed time is accurate to a few milliseconds regardless of display refresh rate or background throttling.

Will it keep running if I switch tabs?

Yes. Because the elapsed time is computed from the start timestamp, switching tabs or minimizing the browser doesn't lose any time — the display catches up instantly when you return.

Can I recover lap times after I refresh the page?

No — laps exist only in the page's memory while the stopwatch is running, so refreshing or closing the tab clears them. Note down or screenshot important lap times before navigating away.

Is the Stopwatch free?

Yes, the Stopwatch is completely free with no usage limits. No signup, no account and no installation required.

Does the Stopwatch work on mobile?

Yes. The Stopwatch is fully responsive and works in any modern browser on phones, tablets and desktops.