WhenMathInterval Timer
Define a work phase and a rest phase, plus how many rounds. Start the sequence and see the current phase and time remaining in it.
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Worked example
With 30 seconds of work and 10 seconds of rest configured, checking the sequence at 35 seconds of total elapsed time shows the rest phase active with 5 seconds remaining, since the first 30 seconds belonged to work and the following 5 fall inside the 10-second rest window. Check that same sequence again at 42 seconds elapsed instead, and it now reports round 2, work phase, with 2 seconds remaining, since a full 40-second work-and-rest cycle has already completed.
Common mistakes
- Assuming a phase change plays a sound or vibration automatically. This only updates the on-screen display, with no audio cue of its own.
- Changing the work or rest duration fields while the timer is running. Reset first, since a running sequence keeps using the durations that were active when it started.
Limitations
This is a browser-local utility with no background guarantee. It does not keep running accurately if the tab is closed, so an interval that needs to survive a closed tab requires a dedicated app instead.
Frequently asked questions
- Can work and rest durations be changed after starting?
- Reset the timer first, then adjust the fields before starting again, since a running sequence keeps using whatever durations were set when it started.
- Does the timer stay accurate if the tab loses focus?
- Yes, phase position is recomputed fresh from real elapsed time on every update rather than by counting ticks, so returning to the tab after any gap shows the correct current phase immediately.