Online Stopwatch with Laps

How to use the online stopwatch

This browser-based stopwatch measures elapsed time down to the centisecond (hundredth of a second). Press Start to begin timing. Press Lap to record a split time without stopping the clock — useful for tracking intervals during runs, workouts, experiments, or any activity where you need multiple checkpoints. Press Pause to freeze the display, and Reset to clear everything and start over.

What are laps and split times?

A lap (also called a split time) records the time elapsed since the last lap — not since the start. This is different from the total time, which shows how long the stopwatch has been running overall. For example, if you're running 400-meter laps and your first lap is 1:30 and your second lap is 1:25, the total time after two laps is 2:55. The lap table shows both the individual lap duration and the cumulative total, so you can track your pace at a glance.

Common uses for a stopwatch

• Running and athletics: Track mile or kilometer splits to monitor pace consistency during training.
• Science experiments: Time chemical reactions, physical processes, or biological observations with centisecond precision.
• Cooking and baking: Time individual steps in a recipe that requires precise timing.
• Productivity sprints: Use the Pomodoro Technique by timing 25-minute focused work intervals.
• Speed cubing and puzzles: Measure solve times for Rubik's cubes, jigsaw puzzles, or other timed challenges.
• Classroom activities: Teachers use stopwatches for timed quizzes, presentations, and science labs.

Stopwatch vs. countdown timer

A stopwatch counts up from zero — it measures how much time has passed. A countdown timer counts down from a set duration — it tells you how much time remains. Use a stopwatch when you don't know how long something will take and want to measure it. Use a timer when you have a fixed duration (like 10 minutes for boiling eggs or 25 minutes for a Pomodoro session). Both tools are available on this site — try the Countdown Timer for duration-based timing.

Technical details

This stopwatch uses Date.now() for timing, which provides millisecond-level accuracy. The display updates every 10 milliseconds (centisecond precision). The timer runs entirely in your browser — no data is sent to any server, and the stopwatch works even if your internet connection drops after the page has loaded. Note that modern browsers may throttle JavaScript timers in background tabs, so keep the tab visible for the most accurate results.

Related tools

• Countdown Timer — set a timer for a specific duration.
• Online Alarm Clock — set an alarm for a specific time.
• Meeting Planner — find overlapping hours across timezones.
• World Clock — see the current time in 60+ cities.