This timer runs the 52/17 rule: 52 minutes of focused work, then a 17-minute break. The numbers were not designed — they came from time-tracking data, where the most productive users tended to work in roughly that rhythm.
The striking part is not the 52. It is the 17. Those people took long, real breaks, and that is the half of the method most people quietly skip.
The break is the method
A 17-minute break feels indulgent, which is exactly why it gets cut to five. But the reason the rhythm works is that the break is long enough to actually leave the task — go outside, eat something, let your attention wander — so the next 52 minutes start fresh instead of tired.
If you only keep one thing from 52/17, keep the long break. A 52/7 rhythm is just a slightly longer Pomodoro with worse recovery.
Treat the numbers loosely
Nobody becomes productive at minute 52 and useless at minute 53. The finding was a pattern, not a law: roughly an hour of genuine focus, then a genuine rest. If 50/15 or 55/20 fits your day better, use that — the timer settings below let you adjust both.