There is no single number. How long you can focus depends on the task, your interest, your rest and your surroundings. The famous “8-second attention span” has no traceable source, and the “10 to 15 minutes” rule for lectures is not backed by primary data. Plan blocks of work with breaks, then adjust them to what you notice.
What does attention span mean?
Attention span is how long you can keep your attention on one task before your mind drifts or your performance drops. Psychologists usually call this sustained attention or vigilance, and they measure it on a specific task, such as spotting a rare signal on a screen.
That detail matters. There is no general “attention span” you carry around like a height or a shoe size. Psychology lecturer Dr Gemma Briggs told the BBC that the idea of an average attention span is “pretty meaningless” because attention is “very much task-dependent”.
How did the goldfish comparison start?
With a number nobody could source. The claim that human attention fell from 12 seconds in 2000 to 8 seconds, one second less than a goldfish, was repeated widely in the press, as the BBC’s More or Less reported in 2017. The programme followed the trail:
- It traced the figure to a 2015 corporate marketing report, which had copied it from a statistics website rather than measuring it.
- According to the BBC, the organisations that website listed as sources could find no record of research behind the numbers.
- Attention researchers the BBC spoke to had no idea where the numbers came from.
The goldfish part is wrong too. Fish behaviour researcher Professor Felicity Huntingford told the BBC that goldfish “have become a model system for studying the process of learning and the process of memory formation”.
What about the “10 to 15 minute” rule?
This one sounds more scientific, and it shaped how some universities design lectures. Neil Bradbury reviewed the evidence in 2016 and found that the most often cited source for the 10 to 15 minute decline “barely discusses student attention at all”. His conclusion: the available primary data do not support a 10 to 15 minute attention limit. The most consistent finding was that attention varied more between teachers than between teaching formats.
What does research on sustained attention actually show?
The research points in a few consistent directions, and none of them gives a universal time limit.
- Performance on monotonous tasks declines with time. As Klein and Feltmate’s 2025 review describes, lab research since Mackworth’s studies in 1948 has repeatedly found that people detect fewer rare targets the longer a watch goes on. This is called the vigilance decrement. The same review notes that the decline tends to be larger when the task is more demanding.
- Short switches away can help. In a 2011 experiment by Ariga and Lleras, people doing a long visual monitoring task showed a steep drop in performance. When they briefly switched to recalling a few digits during the task, the drop did not appear.
- Minds wander a lot. Killingsworth and Gilbert (2010) sampled people’s thoughts through a smartphone app and found they were thinking about something other than what they were doing almost as often as about what they were doing.
Put together: attention does fade on long, dull tasks, the harder the task the sooner that shows, and planned breaks or switches are a reasonable response. But the exact minutes depend on the task and the person.
Why are 25, 52 and 90 minute blocks conventions, not laws?
Popular work intervals come from practice, app data and sleep research, not from a measured human limit.
| Block | Where it comes from | What the evidence is |
|---|---|---|
| 25 min + 5 break | Francesco Cirillo, the Pomodoro Technique, created in the 1980s with a tomato-shaped kitchen timer | A 2025 scoping review (Ogut) found timed Pomodoro breaks consistently improved focus and reduced fatigue, but the studies were varied and short term |
| 24 or 12 min blocks | A 2023 study by Biwer and colleagues with 87 university students over one day of self-study | In Biwer et al., fixed breaks gave less fatigue and more concentration than breaking at will, with the same task completion |
| 52 min + 17 break | DeskTime, 2014 time-tracking data from its most productive users | DeskTime’s own observational app data; its 2021 repeat found 112 + 26 |
| 90 min | The basic rest–activity cycle Nathaniel Kleitman proposed from sleep cycles | Cycles of roughly 90 minutes are clear in sleep; whether the same cycle drives waking focus is still debated |
| 10–15 min | Common wisdom about lectures | Not supported by primary data, according to Bradbury (2016) |
Each of these is a useful starting point. None of them is the correct length for everyone.
So how long should you focus at a time?
Pick a block by how the task feels today, not by a rule:
| Situation | Try | Timer |
|---|---|---|
| You cannot get started | 10 to 15 minutes, one small step | 10 minutes, 15 minutes |
| Studying, admin, routine work | 25 minutes, 5 minute break | 25/5 |
| Writing, coding, problem sets | 50 minutes, 10 minute break | 50/10, 52/17 |
| Deep work you are absorbed in | 60 to 90 minutes | 1 hour, 90 minutes |
| You hate fixed intervals | Work until focus fades, then rest | Flowtime |
Every length is available as a plain countdown too: 5, 20, 30, 45 minutes, or 2 hours.
How can you test your own attention span?
Online “attention span tests” measure one task for a few minutes. A more useful test is a week of your own work:
- Choose one kind of task, for example reading for a course.
- Start a 25-minute timer and note the time whenever you catch your mind drifting.
- Write down one number after each block: how focused you felt, from 1 to 5.
- Try a longer block (45 or 50 minutes) on another day with the same kind of task.
- Compare after a week. Keep the length where your scores stayed high and you finished the most.
Repeat for a different kind of task. You will likely find that your focus span for writing is not the same as for reading or email, which is exactly what the research predicts.
How can you focus for longer?
- Make the task specific. “Draft section two” holds attention better than “work on the report”.
- Remove the easy exits. Put your phone in another room and close tabs you do not need.
- Plan the break before you start. Knowing a break is coming makes it easier to stay put until then.
- Move during breaks. Stand up, walk, look out a window. Avoid scrolling, which rarely feels like rest.
- Keep the sound steady. Quiet, lyric-free sound or silence. See how to study with music.
- Work next to someone. Body doubling helps many people start and keep going.
The short version
Nobody has an 8-second attention span, and nobody has a fixed 25, 52 or 90 minute one either. Start with a 25/5 timer, notice when your focus fades, and move up or down from there. For a deeper comparison of the two most common blocks, read Pomodoro 25 vs 50 minutes.