Online Stopwatch
A clean count-up stopwatch with laps and splits. Start, pause, resume and record lap times with millisecond accuracy - no app needed.
Updated September 2026 · Written and verified by Akash Pandey
Online Stopwatch
How to use the stopwatch
- Press Start to begin counting up.
- Press Lap to record the current time without stopping the timer.
- Press Stop to freeze the timer and review your laps, then Resume to continue.
- Use Reset to clear everything (hold to confirm if laps exist).
Timing is driven by the monotonic performance.now() clock, so it stays smooth and accurate even if the browser tab is busy or backgrounded.
Frequently asked questions
How accurate is the stopwatch?
It timestamps laps with performance.now(), the browser's high-resolution monotonic clock, so it is accurate to well under a millisecond while the page is focused.
Does it keep running in another tab?
Laps are stamped on real time, so durations stay correct even if the tab is throttled in the background.
Can I export my laps?
The lap list is shown on screen; use your browser's print or copy tools, or copy the lap table directly with the copy button.
Is it free and private?
Yes. It runs locally with no account, no ads overlaying the timer, and no data collected.
How long can it run?
Indefinitely - elapsed time grows as long as the page is open.
Does the stopwatch continue running if I switch tabs?
Yes. Elapsed time is calculated using timestamps (performance.now()), so time tracking remains accurate even if the tab is backgrounded or minimized.
How many lap splits can I record?
You can record unlimited lap splits during a session. Each split displays elapsed interval time alongside cumulative elapsed duration.
What precision does this online stopwatch provide?
The stopwatch measures time to hundredths of a second (centiseconds), which is sufficient for athletic timing, study sprints, and workflow tracking.