25/5 vs 50/10: which Pomodoro interval should you actually use?

The original Pomodoro is 25 minutes on, 5 minutes off. Cal Newport's deep-work crowd uses 50/10 or 90/15. People asking which is "better" are asking the wrong question — the right one is what task am I doing?

When 25/5 wins

• Email triage, code review, admin work.
• Studying flashcards, vocabulary, problem sets.
• Days where you can't sit still — short bursts beat heroic intent.
• ADHD days where 25 minutes is already a stretch.

When 50/10 wins

• Writing essays, articles, or documentation.
• Implementing a feature in code.
• Reading dense academic papers.
• Design work that needs warm-up time.

When 90/15 wins

90 minutes lines up with your body's natural ultradian rhythm — you'll feel a real attention dip around then. Use it for the one or two deepest blocks of your day: architecture, exam-day study, the hardest piece of a project. Two of these is a great day.

The actual rule

Pick the shortest interval that lets you reach the work. Most of the time that's 25/5. When 25 isn't enough to load the problem, go 50/10. When even 50 feels rushed, go 90/15. All three are one click apart in Promodify.