Rest length should follow the goal of the session. These are the usual prescriptions; the countdown is the easy part, holding to the number is the hard part. Press any row to load that rest.
Press your rest length in the table below and it starts running, or set it by hand and press Start. Begin the next set when the alert sounds. Naming the timer after the exercise makes the browser tab read like a running order, which is useful when you are working through a list.
It depends on what you are training for, not on how tired you feel. Heavy sets of 1 to 5 reps need 3 to 5 minutes so the next set is not limited by fatigue; sets of 6 to 12 reps need 60 to 90 seconds; sets above 15 reps need only 30 to 45 seconds. See the table above for the full breakdown.
For repeated rounds use the interval timer — it restarts the same length on its own and beeps between rounds. This page times one set, rest or hold at a time.
Yes. It is a web page, so it opens in any phone or laptop browser with no app and no account. The alert plays from the page, so keep the screen on and the volume up.