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Become a better student · Module 1: Memory

Spread it out: why spacing beats cramming

The same number of hours, split across weeks instead of crammed into one night, stays with you for much longer.

Written by the Brainhub Editorial Team Cites published research Updated 13 Oct 2026 5 min read

The course unlocks one lesson at a time. You can read this now, but it only counts once you’ve finished Stop re-reading.

Key takeaways

1. What the spacing effect is

The spacing effect is one of the most reliable findings in the science of learning. If you study something in several shorter sessions with gaps in between, you remember it for longer than if you spend the same total time on it in one go.

A review that pulled together hundreds of spacing experiments found the effect again and again, across different ages, materials and tests.[1]

2. How long should the gaps be?

A large online study tested over 1,000 adults on facts they learned, with different gaps between study sessions and different delays before the final test. The best gap grew with the delay: to remember something for a few weeks, review it after a few days; to remember it for months, wait a week or more between reviews.[2]

As a rule of thumb, aim for a gap of roughly a tenth to a fifth of the time until you need the information. Too short and it’s just cramming in two parts. Too long and you’ve forgotten too much to rebuild easily.

Exam is in…
Review a topic about every…
1 week
1 to 2 days
1 month
4 to 6 days
3 months
1 to 2 weeks
6 months or more
3 to 4 weeks

3. Why cramming feels better

In one study, students learned vocabulary with flashcards either in one big spaced stack or in small crammed batches. Spacing worked better for 90% of them, yet most believed cramming had worked better.[3]

Cramming gives a feeling of fluency: everything is fresh, so it feels learned. That feeling fades fast. Spaced reviews feel harder because you’ve partly forgotten, and that effortful recall is exactly what strengthens memory.

Cramming is borrowing memory you’ll have to pay back. Spacing is putting it in the bank.

4. Putting it into your week

Rotate subjects

Instead of a whole evening on one subject, do 2 or 3 shorter blocks on different topics. Each topic comes round again a few days later.

Keep a review list

At the end of each lesson, note the topic and the date. Come back to it with a quick test 2 to 3 days later, then a week later.

Start earlier, not longer

Starting revision 8 weeks out with 30 minutes a day beats 8 hours the weekend before.

For parents: Ask to see the revision plan, not the hours. Good plans revisit every topic more than once.

Try it now

Test yourself on this page

Answer in your head first, then check.

  1. 1. What is the spacing effect?

  2. 2. If the exam is three months away, roughly how often should you revisit a topic?

  3. 3. Why do students keep cramming even though it works worse?

Your next steps

  • Write your exam dates at the top of a page and count the weeks.
  • List your topics and give each one a first review date this week.
  • Set a phone reminder to revisit each topic after the gap.

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Sources

  1. Cepeda, N. J., Pashler, H., Vul, E., Wixted, J. T. and Rohrer, D. (2006). Distributed practice in verbal recall tasks: a review and quantitative synthesis. Psychological Bulletin, 132(3), 354–380. doi:10.1037/0033-2909.132.3.354
  2. Cepeda, N. J., Vul, E., Rohrer, D., Wixted, J. T. and Pashler, H. (2008). Spacing effects in learning: a temporal ridgeline of optimal retention. Psychological Science, 19(11), 1095–1102. doi:10.1111/j.1467-9280.2008.02209.x
  3. Kornell, N. (2009). Optimising learning using flashcards: spacing is more effective than cramming. Applied Cognitive Psychology, 23(9), 1297–1317. doi:10.1002/acp.1537

This guide is general study advice. Every student is different. A teacher can help you work out what fits.