Francesco Cirillo invented the pomodoro technique as a university student in the late 1980s, and named it after the tomato-shaped kitchen timer he used. So the canonical answer to “why 25?” is: that’s where his timer happened to land.
But the number has stuck for forty years across millions of users. Either it’s pure inertia, or there’s something about ~25 minutes that genuinely fits the way human attention works. I don’t know which yet — and that ambiguity is what makes the question worth chewing on.
Threads to dig into:
- Research on sustained attention windows — does 25 map to anything biological?
- Whether 25 is just “long enough to feel meaningful, short enough to not feel daunting”
- Why 20 feels too short and 40 feels long, at least to me — is the cliff personal or universal?
- Variants people swear by: 50/10, 90/20, the deep work camp’s longer blocks