Spaced repetition: how to remember what you revise
Review material at increasing gaps to remember it long term, with an example schedule and the Leitner box system.
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On this page
What is it?
Spaced repetition means reviewing material at increasing intervals instead of all at once. We forget new information quickly unless we revisit it, and each well-timed review makes the memory last longer. A 2013 review of study techniques rated distributed practice as having high utility, and the IES practice guide also recommends spacing learning over time.
Cramming can help you pass a test tomorrow, but spaced practice usually leads to better long-term retention.
Key formulas and ideas
- Example schedule: review after 1 day, 3 days, 7 days and 14 days.
- If you forget something, shorten the gap and review again.
- Leitner box system: cards you get right move to a box reviewed less often; cards you get wrong return to the first box.
- Combine with active recall by testing yourself at each review.
Worked examples
Example 1: Build a schedule
Question: You learn a topic on 1 March. Plan reviews after 1, 3, 7 and 14 days.
- 1 day later: 2 March.
- 3 days later: 4 March.
- 7 days later: 8 March.
- 14 days later: 15 March.
Answer: 2 March, 4 March, 8 March, 15 March
Example 2: Leitner boxes
Question: Explain how a three-box Leitner system works.
- New cards start in Box 1, reviewed daily.
- A correct answer moves a card up a box (reviewed less often).
- A wrong answer sends the card back to Box 1.
Answer: Cards you know are reviewed less often; hard ones return to daily review
Example 3: Cramming versus spacing
Question: Why is studying for 1 hour on each of 5 days better than 5 hours in one day?
- Spacing gives time to forget a little, so each review needs effort.
- That effort makes the memory stronger and longer lasting.
Answer: Spaced study builds stronger long-term memory
Common mistakes
- Reviewing only once after learning.
- Leaving all revision until the last week.
- Reviewing material you already know well too often.
- Not testing yourself during reviews.
Practice questions
Frequently asked questions
How far ahead should I start?
The earlier the better. Even a couple of weeks gives room for several spaced reviews before an exam.
How far ahead should I start?
The earlier the better. Even a couple of weeks gives room for several spaced reviews before an exam.
Related guides
Active recall: the best way to revise (with examples)
Learn why testing yourself beats rereading, and four simple ways to use active recall: flashcards, blank-page recall and practice questions.
KS3GCSEA-LevelMiddle School+3Interleaving: mix topics in your revision to remember more
Learn why mixing question types in one session can improve long-term learning, with an example maths and science session plan.
GCSEA-LevelHigh SchoolAPHow to make a revision timetable you can stick to
Plan backwards from your exam dates and use focused study blocks with breaks, with a simple way to share your time between subjects.
KS3GCSEA-LevelMiddle School+3Sources and review
- Dunlosky et al. (2013), Improving Students' Learning With Effective Learning Techniques, Psychological Science in the Public Interest
- IES practice guide: Organizing Instruction and Study to Improve Student Learning (2007)
Reviewed by StudyMorrow editorial review on 5 Nov 2026.