7 Minute Timer
Seven minutes is 420 seconds. It is one of the lengths that will not divide an hour: eight runs come to 56 minutes, four short, so seven is a size you choose rather than a slot you fill.
7:00
Nothing plays until you press start.
420 seconds, and no clean fit
Five, six, ten, twelve, fifteen, twenty and thirty all divide 60 exactly. Seven does not. Eight runs land at 56 minutes and nine overshoot at 63, so a day built out of seven-minute blocks drifts against the clock. If you want blocks that stack into an hour, use six, ten or twelve. Seven is for tasks that genuinely take seven.
Talks that fit inside seven
A Pecha Kucha talk is twenty slides at twenty seconds each, advancing automatically, which comes to exactly six minutes and forty seconds. A seven-minute timer covers a full deck with twenty seconds to spare, and it is the usual practice length for that format. The shorter cousin, Ignite, is twenty slides at fifteen seconds, five minutes flat, on the 5 minute timer.
The seven-minute circuit
The widely copied seven-minute workout is twelve exercises of thirty seconds with roughly ten seconds between them. Run end to end that is nearer seven minutes fifty than seven, so the name rounds down. A seven-minute timer times the label rather than the circuit; if you want the whole thing, set eight.
Before you rely on it
Time is measured against the system clock, so the count survives a backgrounded tab or a switched window without drifting. The sound is less dependable, and a phone that has gone to sleep may not fire it at all. Use a real alarm for anything where missing zero has a cost, such as medication, an exam or a cooking step that burns.