Method / assumptions / examples
How this calculation works
The result is deterministic: the same measurements always return the same estimate. Here is the relationship and where real-world results can differ.
Formula
Elapsed time = current timestamp − start timestamp − paused duration
The display is derived from timestamps rather than by counting interface updates. For a countdown, remaining time is the chosen duration minus elapsed time, bounded at zero. This lets the display catch up after a delayed browser render instead of permanently losing ticks.
Worked example
Examples
Set 05:00 and start. Pausing preserves the remaining duration; resuming continues from that point.
Start the stopwatch, pause during an interruption, and resume to continue from the accumulated elapsed time.
Common mistakes
What to check before using the result
- Keep this tab open and your device awake when the finish time matters; browser and operating-system power controls can delay alerts.
- Pause the stopwatch when excluded time should not count; resuming keeps the accumulated elapsed duration.
- A browser timer is convenient for everyday tasks, but it is not a certified timing or safety device.
FAQ
Frequently asked questions
Will the timer continue in a background tab?
Elapsed time is recovered from timestamps, but browsers may throttle background updates and delay the audible finish alert.
How accurate is the stopwatch?
It is appropriate for everyday timing. Display updates, user reaction time, device sleep, and browser scheduling make it unsuitable for certified measurements.
Does CalcDB store my timer session?
The timer runs in your browser. Reloading or closing the page can clear its current countdown or stopwatch progress.