Short answer: there is little research, and the best of it comes from the Netherlands. In one study, fixed breaks left students less tired and more focused than breaks taken on feel, with the same amount of work done. In the other, there was no winner. What holds in both: the 25 minutes are not a law. A 12-minute block did just as well.
The Pomodoro doesn't work because of the number 25. It works because the break is set before you start, so nobody has to decide halfway through whether they've done enough.
Where the 25 minutes come from
The technique was invented by Francesco Cirillo in the late 1980s, when he was a university student in Rome struggling to stay with his studies. He picked up a tomato-shaped kitchen timer — pomodoro in Italian — and made a deal with himself to work one block without interruption. The fixed form he later described: 25 minutes of work, a 5-minute break, and a longer break after four rounds.
So the 25 minutes are one student's practical choice, not a research finding. That doesn't make them wrong, but it does mean there is room to adjust them — especially in a classroom.
What the research shows
The Pomodoro is far more popular than it is studied. The two studies that really matter were both done in the Netherlands, with students working on their own coursework rather than a lab task.
Maastricht, 2023: fixed breaks versus breaks on feel
Felicitas Biwer and colleagues at Maastricht University followed 87 bachelor's and master's students through a real study day. Some took a break whenever they wanted. The others worked in fixed blocks: 24 minutes of work and a 6-minute break, or 12 minutes of work and a 3-minute break.
Students who chose their own breaks worked longer at a stretch and took longer breaks. They reported more fatigue and distraction, and less concentration and motivation. How much work got done did not differ between groups, but the fixed-break groups did it in less time. And the short 12-plus-3 schedule did no worse than the long one.
A 2025 follow-up: no winner
Smits, Wenzel and De Bruin repeated the comparison with 94 students in a two-hour study session. This time the options were classic pomodoros (25 plus 5), breaks on feel, and Flowtime: you choose when to stop, and the break grows with how long you worked.
Here the Pomodoro came off worse. In that group, fatigue rose faster as the session went on, and in both groups with a fixed break schedule, motivation dropped faster than with breaks on feel. Over the whole session, though, this made no difference to overall fatigue or motivation, nor to productivity or work completed.
Maastricht 2023 | Follow-up 2025 | |
|---|---|---|
Participants | 87 students | 94 students |
Schedules | breaks on feel · 24 + 6 · 12 + 3 | breaks on feel · 25 + 5 · Flowtime |
Work completed | no difference; fixed breaks finished faster | no difference |
How it felt | fixed breaks: less tired, more focused | Pomodoro: fatigue rose faster over the session |
What you can and can't take from this
These are university students, not pupils. Both studies worked with people around twenty studying on their own. They say nothing directly about a class of 28 twelve-year-olds.
This is one session. One day or two hours, not a school year. Whether the effect lasts once the technique becomes a habit is unknown.
Fixed breaks don't make anyone smarter. Neither study found more work completed. The possible gain lies in how the work feels and how long it takes.
Block length isn't sacred. Twelve minutes did as well as twenty-four. For anyone working with a class, that is the most useful finding.
Why 15 minutes in the classroom
In LudensFlow's Pomodoro activity, the work block defaults to 15 minutes and the break to 5. That is a deliberate departure from Cirillo, for three reasons.
A class isn't one student. Someone working alone notices when their attention slips. In a class, the first person to drift sets the noise level for the rest of the row. A shorter block cuts the final minutes, which is when that usually happens.
It fits a lesson. Ten minutes of instruction and two rounds of 15 plus 5 fill a 50-minute lesson exactly. With 25-minute blocks, only one round fits after the explanation — and then it's no longer a technique, just quiet work.
he research allows it. The shortest schedule in the Maastricht study did no worse than the longest. There is no reason to hold on to 25.
The table below is a working guideline to adjust to your own group, not a measured norm.
Situation | Work | Break |
|---|---|---|
First time, or a restless group | 10 min | 3 min |
Standard within a lesson | 15 min | 5 min |
Exam class or study hour, group knows the technique | 25 min | 5 min |
Once a group has worked with fixed blocks for a few weeks, let students occasionally choose when the break comes. The follow-up study suggests a fixed rhythm may cost motivation over time, and a group that has mastered the technique needs the structure less.
What the break should be
The break isn't a reward after the work; it's half of the technique. In A Mind for Numbers, Barbara Oakley describes two modes of the brain: the focused mode, where you do the work, and the diffuse mode, where what you've learned settles into place. The second only starts once the first stops.
In practice that means getting up, walking around, looking out of the window. Carrying on with the task doesn't count as a break, and neither does a quick look at a phone — that's focused activity again, just on something else.
Common mistakes
Carrying on because it's going well. One student can do that; a class can't. Half stops, half keeps working, and nobody really gets a break.
Using the break to debrief. Then it's no longer a break. Debrief after the break, not during it.
Answering questions during the work block. One question out loud pulls the whole row out of focus. Have students write questions down and answer them at the changeover.
Keeping time yourself. Watching the clock while walking the room means doing two things by halves. A visible timer takes that over, for you and for the group.
The same schedule every day. A rhythm that never changes becomes wallpaper. Let the length move with the task.
The number 25 comes from a student's room in Rome, not from a lab.
What works is that the break is already set.
Want to try it with your own task? The Pomodoro is ready to go, with a timer, adjustable blocks and a screen that shows only the clock.
Sources
Biwer, F., Wiradhany, W., Oude Egbrink, M. G. A., & de Bruin, A. B. H. (2023). Understanding effort regulation: Comparing 'Pomodoro' breaks and self-regulated breaks. British Journal of Educational Psychology, 93(S2), 353–367.
Smits, E. J. C., Wenzel, N., & de Bruin, A. (2025). Investigating the Effectiveness of Self-Regulated, Pomodoro, and Flowtime Break-Taking Techniques Among Students. Behavioral Sciences, 15(7), 861.
Cirillo, F. (2018). The Pomodoro Technique. Currency.
Oakley, B. (2014). A Mind for Numbers. TarcherPerigee.