Rehearsal checkpoints
Record a lap after each section of a talk. A cumulative timestamp of 02:08.540 following 01:03.120 produces a second split of 01:05.420.
Measure every split
Ready to start
00:00:00.00
Timing uses the browser’s monotonic clock. Up to 1,000 laps. Keep this page open; results are not saved after a refresh.
Laps0
Fastest split—
Record a lap to build your split table, then copy or export it.
Inputs and results are processed in this browser. This tool does not upload your entries or retain them after a page refresh.
How to use the Stopwatch
- 01
Start the stopwatch when your activity begins.
- 02
Record a lap at each checkpoint; timing continues while the table grows.
- 03
Pause to exclude a break, resume when ready, and copy or download the recorded laps.
Examples
Repeated task comparison
Use the example laps to see three task durations. The fastest label refers to the shortest split, rather than the lowest cumulative timestamp.
How lap splits are calculated
Each split equals the current recorded elapsed time minus the preceding lap timestamp. The first split starts at zero. Paused time is excluded, so restarting after a break continues the same measured activity.
Timing precision and display
The large display shows hundredths of a second and the lap export shows milliseconds. Display precision does not guarantee measurement accuracy: button reaction time, browser scheduling, and device behavior affect the result.
Keep a record before resetting
Reset clears both elapsed time and laps. CSV includes the lap number, split, and cumulative duration. Hours can exceed 23 because these values are elapsed durations, not times of day.
What to know
- Maximum 1,000 recorded laps.
- The browser is not a certified timing instrument; device sleep may affect elapsed time.
Common questions
Does it keep timing in another tab?
Elapsed time is recalculated from a monotonic browser clock when updates run. Background tabs may update less often. Device sleep behavior varies, so keep the device awake for important timing.
Can I edit a recorded lap?
Recorded laps are fixed in this stopwatch. Export the table for further analysis, or enter times in the lap time calculator.
Will it save my laps?
No. Download or copy them before refreshing, resetting, closing, or navigating away.