What a 90 minute timer is for
Ninety minutes is one sleep cycle, one football match and one full ultradian block — the natural stretch of concentration before the body asks for a genuine rest.
What people set it for
- A full deep-work block before a real break
- One sleep cycle, for planning a nap or a night
- A film, a match or a long rehearsal
- Long bakes, proving and slow cooking
How this timer behaves
The countdown is stored as the moment it should finish, not as a number being decremented, so switching tabs or minimising the window cannot make it run late, and pausing and resuming is exact. Through the final minute the readout and its ring turn red and pulse, giving you a warning before the alert rather than only at it.
It does not start on its own. The alarm is generated in your browser, and browsers keep audio silent until you interact with the page — so a timer that started by itself would be a timer that finished in silence. One tap on start is what makes the sound work.