Stopwatch

An accurate stopwatch in your browser

A stopwatch is essential for athletes, coaches, students, cooks and anyone who needs to time an activity. This one is accurate to a hundredth of a second and uses the browser's high-resolution timer, so it isn't affected by changes to your device clock.

How to use it

1. Press “Start” or the space bar to begin.
2. Press “Lap” (or L / Enter) to record the current lap without stopping.
3. Pause and resume to continue where you left off.
4. Press “Reset” (or R) to start over.
5. Copy the lap table or download it as CSV for Excel.

Lap tracking

Each lap records its individual time and the running total. With three or more laps, the fastest lap is highlighted in green and the slowest in red, making it easy to analyze your pace.

Common uses

• Sport: running and swimming splits, HIIT intervals.
• Study: timing how long each question takes when practicing for exams.
• Work: tracking task durations to improve estimates and productivity.
• Science: timing lab and school experiments.
• Speaking: rehearsing speeches and presentations.

To count down instead, use the Countdown Timer; for structured focus try the Pomodoro Timer.

Using laps to train smarter

Lap times aren't just numbers — they reveal how you perform. When running, if your early laps are much faster than your last ones, you're starting too fast and burning out. The ideal in longer races is “even” or “negative” splits: laps that are consistent or slightly faster toward the end.

Interval training

Interval workouts alternate hard effort and recovery, such as 30 seconds of sprinting and 90 seconds of walking. Press Lap at the end of each phase to check you held the target durations. Over time, compare your exported tables to see week-by-week improvement.

Accuracy tips

• On a computer, use the keyboard shortcuts — they're faster than clicking.
• On a phone, keep the screen awake in your settings if you need to watch the time continuously.
• Human reaction time is about 0.2 seconds, so manual timing suits training, not official competition.

Frequently Asked Questions

Last updated: 2026-10-20