Stopwatch

More Than Just Start and Stop

Most stopwatch tools do one thing: count up. Ours goes further with lap splits, a full lap history table, average lap time calculation, and keyboard shortcuts so you never need to reach for the mouse between laps.

Features

Millisecond precision — timing displays to the nearest 10ms (hundredths of a second), sufficient for most timing needs short of professional athletics.

Lap recording — hit L or the Lap button during a run to record a split. The display shows both the current lap time and the overall elapsed time simultaneously.

Lap history table — all recorded laps appear in a scrollable table showing lap number, lap time, cumulative time, and whether it was the fastest or slowest lap.

Keyboard shortcuts:

• Space — Start / Pause
• L — Record lap (while running)
• R — Reset (while paused)

Runs in background — if you switch tabs or minimize the browser, the timer keeps running. When you come back, the elapsed time is correct.

Common Use Cases

Interval training and workouts Record lap times for each interval — sprints, swimming lengths, rowing strokes. Review your splits after the session to see where you gained or faded.

Cooking and baking Time multiple stages of a recipe simultaneously. Use the lap button when you put something in the oven, when you start preheating, when pasta goes in — you get a running log of when each step happened relative to the start.

Presentations and speeches Practice with a timer running. Hit lap at each section transition to see how long each part of your talk takes. Identify sections that run over and need trimming.

Studying (Pomodoro tracking) If you prefer not to use a countdown timer, a stopwatch lets you work until you feel ready to break, then check how long you actually focused instead of pressuring yourself to reach a target.

Coding challenges and speed tests Time how long it takes you to solve a problem. Track improvement across sessions by comparing lap times for similar challenges.

Kids' games and competitions Fastest to tie their shoes, quickest to solve a puzzle — the lap feature lets you time multiple contestants and display results clearly.

Stopwatch vs. Timer: Which One to Use?

For baking: use a countdown timer. For exercise splits: use a stopwatch. For a Pomodoro: either works — timer for discipline, stopwatch for flexibility.

Accuracy Notes

Browser-based stopwatches use JavaScript's performance.now() API, which provides sub-millisecond resolution. However, there are practical limits:

Tab throttling: Modern browsers reduce JavaScript execution frequency for background tabs. Our stopwatch compensates by recording the actual wall-clock time at each event rather than counting ticks, so background tab timing remains accurate even if the display pauses.

Display refresh: The display updates every 10–50ms depending on your device. This is a visual limitation only — the underlying timing remains accurate regardless of how often the number on screen refreshes.

For most purposes — from cooking to workouts to presentations — the accuracy is perfectly sufficient. For professional timing (competitive athletics, laboratory measurements), use a dedicated hardware stopwatch.