Four display formats
Choose milliseconds (00:00.000), centiseconds (00:00.00), deciseconds (00:00.0), or seconds (00:00).
00:00.00
Scroll for stopwatch details
Online Stopwatch
Measure elapsed time in a browser, record laps, choose a display format, and export a session as CSV. The controls are available on responsive desktop and mobile layouts.
Lap records
Add lap records during a running session and review the recorded durations in the list.
CSV export
Download lap and session data as CSV for a spreadsheet or another analysis tool.
Display settings
Adjust the font, size, colors, position, background, and fullscreen presentation.
Inspect a lap data example
See how lap splits and cumulative totals fit together in a fixed five-row sample, with matching CSV and JSON downloads.
About elapsed-time updates
The stopwatch derives elapsed time from the browser performance clock rather than assuming that every visible update runs on schedule. Browser throttling can still affect screen refresh, so check the page for important measurements.
Fullscreen and Wake Lock
Fullscreen can request the Screen Wake Lock API when the browser and device support it. Keep this tab open for the session, and note that the browser or device may release Wake Lock. Audio, if used by the page, may be limited by browser permission or device settings.
Use the stopwatch
- 1. Select a display format.
- 2. Start and pause the session as needed.
- 3. Record laps during the session.
- 4. Export the results as CSV.
More time tools
Frequently Asked Questions About Online Stopwatch
How does the stopwatch measure elapsed time?
Elapsed time is derived from the browser performance clock, while the display format is selected in the stopwatch controls. Practical precision depends on the browser and device.
Can I record lap times?
Yes. Record laps during a session, review lap statistics, and export the recorded data to CSV.
What time formats are available?
Choose milliseconds (00:00.000), centiseconds (00:00.00), deciseconds (00:00.0), or seconds only (00:00).
Does the stopwatch run when the tab is not active?
The stopwatch calculates elapsed time from timestamps rather than counting visible update callbacks. Browser throttling can affect screen refresh, so check the page for important measurements.
Can I customize the stopwatch?
You can change fonts, size, colors, position, background, and fullscreen presentation. Settings are kept locally in the browser.