Online Stopwatch - Lap Times & Precision

Precise online stopwatch with lap times. Start, stop, and reset with one click. Free, works in any browser - no install needed.

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Online Stopwatch - Lap Times & Split Timer

A precise stopwatch that runs directly in your browser. Use it for sports timing, cooking, presentations, or any activity that needs accurate time measurement. The lap feature lets you record split times without stopping the clock.

The stopwatch displays hours, minutes, seconds, and milliseconds. Record unlimited lap times while the main timer continues running. Each lap shows both the individual split time and the cumulative total, making it easy to compare segments.

Browser-based stopwatches use the high-resolution performance timer API, which provides sub-millisecond accuracy independent of the system clock. However, background tabs may be throttled by the browser to save resources - keep the tab in the foreground for the most consistent timing.

For interval training, use the lap feature to record each set or rest period. Coaches can time multiple athletes by starting the stopwatch once and recording laps for each runner as they pass. The split-time view makes it easy to identify which interval was fastest or slowest.

If you need a countdown timer instead, check our Timer tool. For measuring meeting duration and calculating its cost, our Meeting Cost Calculator combines elapsed time with participant costs.

How the Stopwatch Works

01Click Start to begin timing
02Use the Lap button to record split times without stopping
03Pause and resume at any point
04Reset to clear all recorded times

Using Lap Times Effectively

Lap times let you measure individual segments within a longer activity - useful for interval training, cooking steps, or presentations. Each lap records both the split time (since last lap) and the total elapsed time. For best accuracy, use a stable browser tab - background tabs may throttle timers. This stopwatch runs entirely in your browser with millisecond precision.

When to Use the Stopwatch

Use this stopwatch for sports timing (running splits, swim laps, workout intervals), cooking (timing recipe steps that need precision), presentations (tracking speaking time per section), testing (measuring task completion times for usability studies), and any activity where you need to measure elapsed time with split tracking.

Common Use Cases

Time running intervals and rest periods during workouts
Record lap times for swimming, cycling, or track training
Time cooking steps that require precise durations
Measure speaking time for presentation rehearsals
Track task completion times for productivity analysis and usability testing

Expert Tips

Use the lap feature for interval training - record each work and rest period to analyze your pace consistency.
Keep the stopwatch tab in the foreground for the most consistent display updates. Background tabs may show slightly delayed visual updates.
For presentations, set target times per section and use laps to track when you move to the next section - this helps you stay on schedule.
Compare split times across sessions to track improvement. Copy your lap times to a spreadsheet for trend analysis over weeks or months.

Frequently Asked Questions

How accurate is a browser-based stopwatch?→

Modern browsers use the Performance API for timing, which provides sub-millisecond resolution. For practical purposes, a browser stopwatch is accurate enough for sports timing, cooking, and productivity tracking. It is not suitable for scientific measurements requiring microsecond precision.

Will the timer stop if I switch tabs?→

The timer continues running, but browsers may throttle the display update in background tabs. The elapsed time remains accurate when you return - only the visual update frequency is affected. Keep the tab in the foreground for the smoothest display.

Can I save my lap times?→

Lap times are displayed on screen and persist during your session. To save them permanently, copy the lap time list before resetting. The times are lost if you close the tab or refresh the page.

What is the difference between split time and lap time?→

Split time is the total elapsed time from start. Lap time is the duration of the individual segment since the last lap. For example, if your splits are 0:30, 1:05, 1:42 - your lap times are 0:30, 0:35, 0:37.

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