Practical guide
How to Use a Stopwatch and Read Lap Times
A stopwatch measures elapsed time, and laps let you split that time into parts. The SmartEdgeTools Stopwatch shows time as minutes, seconds, and hundredths of a second, and records laps while it runs. This guide explains how to use it for practice, workouts, cooking, and timing tasks, and how to read the two times shown for each lap.
By Ather Saud · Updated on November 1, 2026
Start, pause, resume, and reset
Press Start to begin, Pause to stop the count without losing it, and Start again to resume from the paused time. The button label changes to Resume when there is a paused time. Press Reset to clear the time and all laps and return to 00:00.00. Reset does not save the laps, so note any times you need before resetting.
The display format is MM:SS.CS, where CS is hundredths of a second. For example, 01:23.45 means 1 minute, 23 seconds, and 45 hundredths. The timer updates about every 30 milliseconds in the browser, and the display rounds down to hundredths, so very short intervals should be treated as approximate.
How laps work
Press Lap only while the stopwatch is running; the button is disabled when it is paused or at zero. Each lap row shows two times: the lap duration, which is the time since the previous lap, and the total elapsed time at that lap. The first lap duration equals the total time at that lap, because there is no previous lap.
For example, if Lap 1 is pressed at 00:30.00 and Lap 2 at 01:10.00, Lap 2 lasted 40 seconds, while the total time at Lap 2 was 1 minute 10 seconds. Use lap durations to compare parts of a task, and total times to check progress against a deadline or a target.
Practical timing tips
Decide what counts as the start and finish before you start, especially when timing people or tasks. For a race or a practice run, use Lap at each checkpoint rather than stopping and restarting, so the total time stays continuous. For cooking or a work task, use Pause when you are interrupted, so the paused time does not count as working time.
Keep the page open while timing. The stopwatch runs in the browser page, and closing or refreshing the page will lose the current time and laps. If a time matters for a record, write it down or take a screenshot as soon as you finish.
Accuracy limits
A browser stopwatch is suitable for practice, study, workouts, and everyday timing, but it is not a certified timing device. Browser timers, device load, and human reaction time when pressing Start, Lap, or Pause all add small errors. For official races, laboratory measurements, or legal timing, use the timing system required for that purpose.
For fair comparisons, use the same device, the same start and finish rules, and the same lap points each time. A difference of a few hundredths of a second between runs may be reaction time, not a real change in performance.
| Lap | Lap duration | Total elapsed time |
|---|---|---|
| Lap 1 | 00:30.00 | 00:30.00 |
| Lap 2 | 00:40.00 | 01:10.00 |
| Lap 3 | 00:25.00 | 01:35.00 |
Key takeaways
- Time is shown as minutes, seconds, and hundredths: MM:SS.CS.
- Each lap shows both its own duration and the total time at that lap.
- Pause keeps the time; Reset clears time and laps, so save times first.
Frequently asked questions
What is the difference between lap time and total time?
Lap time is the duration since the previous lap. Total time is the elapsed time from the start to that lap.
Can I record a lap while paused?
No. The Lap button is disabled when the stopwatch is not running. Resume first, then press Lap.
Does the stopwatch keep running if I close the page?
No. It runs in the browser page, so closing or refreshing the page loses the current time and laps.
Is a browser stopwatch exact?
It is suitable for everyday timing, but browser timing and human reaction time add small errors. It is not a certified timing device.