How precise is browser timing?

requestAnimationFrame and performance.now keep millisecond-grade reads on modern desktops, but background tabs may stutter on low-power devices.

What do lap rows show?

Each lap records elapsed since start plus split since previous lap — export or screenshot if you need an audit trail.

Space often toggles start/stop while L or a labelled key adds a lap — check the on-page legend.

Does GPS replace this?

Outdoor apps log distance-based splits; a stopwatch still helps indoor treadmills or pool lengths.

Will closing the tab lose data?

Unless the tool auto-saves history, copy lap times before navigating away.

Fullscreen readability?

Zoom the browser or use presenter mode when timing on stage.

Certified races use photo-finish hardware — this is for training and informal measurement.

After the page loads once, core timers often work without network connectivity.

Online Stopwatch

Time Live

Accurate stopwatch with lap times and keyboard control.

About this tool

Online Stopwatch — Accurate stopwatch with lap times and keyboard control. Free, fast and private. Runs entirely in your browser at Quick Calci Tools.

Examples

Common scenarios for the Online Stopwatch.

5 km splits

laps: 5

Lap table with delta per kilometre.

Reaction test

precision: ms

Milliseconds shown for hand-timing drills.

Who uses the Online Stopwatch?

Common scenarios and audiences for this tool.

Run coaches

Capture informal interval data on tracks without wearables.

Speech coaches

Time student monologues against syllabus limits.

Lab technicians

Log incubation windows between manual readings.

Theatre crews

Rehearse cues against director stopwatch calls.

Hobbyists

Time puzzle turns or board-game rounds fairly.

Frequently asked questions

Everything you need to know about the Online Stopwatch.