Free Online Stopwatch with Lap Timer (Hundredths of a Second)

How to use this tool

1. Start the stopwatch. Click the "Start" button to begin counting. The display updates in real time.
2. Record laps. Click "Lap" while the stopwatch is running to record a split time. Repeat as needed.
3. Stop and resume. Click "Stop" to pause the timer. Click "Resume" to continue from where you left off.
4. Export laps. Click "Export CSV" to download your lap times as a spreadsheet-compatible CSV file.
5. Reset. After stopping, click "Reset" to clear the timer and laps. Confirm the prompt when laps are present.

Free online stopwatch with lap timer

This stopwatch measures elapsed time with centisecond precision (hundredths of a second), right in your browser. No download, no sign-up. Start, record laps, stop, and export or copy your splits. A refresh in the same tab restores a running watch and its laps.

How to read the lap table

Each row in the lap table shows three values:

• Lap: the sequential lap number.
• Split: the time elapsed between the previous lap and this one.
• Total: the cumulative elapsed time at the moment this lap was recorded.

The fastest split is highlighted in green (Best); the slowest in red (Worst). These labels appear once you have two or more laps with different split times. A summary also shows the best, worst, average, and total time across recorded laps.

Exporting laps to a spreadsheet

Click Export CSV to download a .csv file compatible with Excel, Google Sheets, and Numbers, or copy the laps to paste them into another app. Each row includes readable times in MM:SS.cc format (or HH:MM:SS.cc for runs over one hour) and numeric millisecond columns for spreadsheet calculations.

Stopwatch precision explained

Timing is based on Date.now() deltas rather than setInterval ticks, so the elapsed time stays accurate even when the browser tab is hidden or JavaScript execution is throttled. The display refreshes via requestAnimationFrame for smooth updates while the tab is active. The clock reads millisecond wall-clock timestamps and floors the display to the nearest lower centisecond. Because it follows the system clock, a clock adjustment during a run may shift the elapsed time.

Common uses

• Running and cycling: lap times for each mile or kilometer.
• Swimming: split times per length or per 100 meters.
• Cooking: time cooking stages.
• Presentations: practice keeping within a time limit per section.
• Coding sessions: rough time-on-task without a dedicated app.
• For one cube solve with inspection and ao5, use the Cube Timer. For min/km or min/mi from a split, use the Pace Calculator.

Keyboard shortcuts

• Space: start, stop, or resume
• L or Enter: record a lap while running
• R, Delete, or Backspace: reset while stopped
• F: enter or exit fullscreen; Escape exits fullscreen

Accuracy vs. dedicated sports timers

Browser-based stopwatches have inherent timing limitations:

• JavaScript timers can be throttled when the tab is not focused or the device is under CPU load. This tool compensates by using Date.now() delta timing rather than accumulating setInterval ticks, but display updates may still lag slightly.
• Typical browser stopwatch latency is on the order of 50–150 ms from button press to recorded time - acceptable for most training and coaching uses.
• Dedicated electronic sports timers (track starter systems, competitive swimming systems) achieve latency under 5 ms and are required for official competition timing. Use this tool for training, practice sessions, and informal timing.