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Exam coming up? Here is when to review, and how.

Spaced Repetition Schedule: When to Review for Exams

Reviewed · 7 sources · By Anthony Falcone

The short answer: Study a topic, then come back and test yourself on it after a gap that fits how far away the exam is. In a study of more than 1,350 people, the best gap for a test 1 week away was about 20–40% of that week (roughly 1.5 to 3 days); for a test a year away it was only 5–10% of the year. Use each review to recall from memory rather than reread: spacing and practice testing are the two study methods a major review rated most useful.2,3

Before you start

  • If exam stress stops you sleeping or eating for days, causes panic attacks, or makes you feel hopeless, talk to a doctor or your school or university health service. That deserves help in its own right, and no revision schedule will fix it.
  • If you have a diagnosed learning or attention difficulty, ask your doctor, teacher or disability service about exam adjustments, such as extra time, as well as about how to study.
  • 20–40% of the time to a test 1 week away was the best gap before reviewing, in a study of more than 1,350 people2
  • 5–10% of the time to a test 1 year away was the best gap: the further off the test, the smaller the share2
  • 839 assessments of distributed (spaced) practice, from 317 experiments, pooled in one meta-analysis1
  • 0.69 vs 0.41 size of the benefit of testing yourself over rereading when the final test was more than a day away, versus less than a day6
  • 0.32 standardised benefit for knowledge of spaced over massed online teaching, pooled from 9 studies in health students and professionals7

What spaced repetition is

Spaced repetition combines two things: testing yourself on the material, and spreading those tests out over time instead of doing them back to back. Researchers call the two parts the testing effect and spaced (or distributed) learning.6

Spacing is backed by a large body of experiments. A 2006 meta-analysis pooled 839 assessments of distributed (spaced) practice from 317 experiments in 184 articles. Its main finding about timing: the gap that gave the best recall grew as the time to the final test grew.1

A large review of ten common study techniques rated only two of them high utility: practice testing and distributed practice, because they helped learners of different ages and abilities on many kinds of tests, including in real classrooms. Rereading and highlighting, which students report relying on heavily, were rated low utility.3

How long to wait between reviews

The clearest answer comes from a study of more than 1,350 people. They learned a set of facts, got one review after a gap of up to 3.5 months, and took a final test up to a year later. For any test date, lengthening the gap first raised the final score and then slowly lowered it, so there was a best gap.2

The best gap got longer the further away the test was, but shrank as a share of that time: about 20–40% of the time for a test 1 week away, and about 5–10% for a test 1 year away.2

In days: with an exam 7 days away, 20–40% is 1.4 to 2.8 days (7 × 0.2 and 7 × 0.4), so review a topic roughly 1.5 to 3 days after you first study it. For material you need in a year, 5–10% of 365 days is roughly 18 to 37 days.2

Past the best gap, scores fell only gradually. So when you are unsure, a gap that is a little long costs less than reviewing straight after learning.2

How to build a spaced repetition schedule for an exam

Work backwards from the exam date. Learn each topic once, early enough that a gap can fit before the exam, then put a self-test on that topic after a gap that suits the time left. For an exam a week away that is roughly 1.5 to 3 days; the further away the exam, the longer the gap in days. Our free Revision Timetable Maker does this arithmetic for you.2

A second or third test on the same material adds more, but with diminishing returns: most of the benefit comes from the first test. Spacing those later tests with longer gaps between them also tends to help, though extremely long gaps may hurt.6

Mixing topics within a session, rather than finishing one topic before starting the next, gave better learning than blocked practice for most materials in meta-analyses, with a medium effect. It may help most with topics that are easy to confuse.6

Active recall and spaced repetition: test yourself in every review

What you do in each review matters as much as when. In two experiments, students read prose passages and then either reread them or tried to write down everything they remembered, without feedback. On a test 5 minutes later, rereading did better. On tests 2 days and 1 week later, the students who had practised recalling remembered substantially more, even though rereading made students more confident.4

Across studies, the advantage is reliable. A 2023 review reports pooled effects of 0.50 and 0.70 (Hedges' g, half a standard deviation or more) for testing over restudying in two meta-analyses, and a larger effect when the final test came more than a day later (0.69) than less than a day later (0.41). It held for multiple-choice, fill-in-the-blank and essay-style practice.6

Check your answers against the correct ones. Testing helps even without feedback, but it helps more with it, and seeing the correct answer matters: being told only 'right' or 'wrong' adds little. With feedback, wrong answers during practice did not harm later performance.6

Keep testing the cards you already know

A common habit is to drop a flashcard once you get it right. In an experiment with foreign-language vocabulary, extra study of a word after recalling it once did nothing for the delayed test, while extra testing on it had a large benefit. The students' own predictions of how well they would do were unrelated to how well they actually did.5

A 2023 review reaches the same conclusion from a wider body of work: compared with dropping items after a single correct answer, carrying on practising them had a medium to large benefit for long-term memory, with an effect size of 0.75 in one meta-analysis.6

Is spaced repetition better than cramming?

For an exam days or weeks away, yes. Across hundreds of experiments, spreading study out gave better recall later than massing it into one session, even with the total study time kept the same, and the best gap depended on when the test came.1,6

Cramming has one real advantage: when the test comes straight after studying, rereading can beat testing yourself. That edge fades fast. The benefit of testing over restudy grows as the delay to the final test gets longer.6,4

It holds outside the lab too. A 2024 meta-analysis of 23 randomised and quasi-randomised studies with 3,371 participants found that spaced online teaching, with sessions at least a day apart, beat massed (all-at-once) online teaching for knowledge, with a small effect (0.32 in 9 studies, rated moderate certainty). Most of the studies were in qualified health professionals, though, not school or university students.7

What to do with this

  • Plan your reviews from the exam date: for an exam a week away, test yourself on each topic roughly 1.5 to 3 days after you first learn it, and use longer gaps in days for exams further away.2
  • In every review, close your notes and recall first (flashcards, a blank page, past questions), then check the correct answers.4,6
  • Keep testing yourself on material you already got right instead of dropping it.5,6
  • Swap rereading and highlighting for practice testing; spread study out instead of cramming the night before.3,1

How sure is this?

  • We could read only the summaries of five sources: the two spacing papers, the review of study techniques and the two testing experiments. We use only their main results and the numbers given in those summaries.1,2,3,4,5
  • The timing study taught people sets of facts. Exams also test understanding and problem solving, so treat the gap percentages as a guide rather than an exact rule, and note that its summary gives the best gap only for tests 1 week and 1 year away.2
  • The 2024 meta-analysis covered mostly qualified health professionals and online teaching; its studies varied widely and most had an unclear or high risk of bias. One author is an associate editor of a journal from the same publisher.7
  • The 2023 review is a narrative review, not a systematic one, written about doctors' continuing education. It was funded by the American Board of Internal Medicine, the American Board of Medical Specialties and the American Board of Family Medicine, which run testing programmes for doctors; the authors say final approval rested with them.6

Common questions

What is the best spaced repetition schedule?

One where the gap before each review fits the time to the exam. In a study of more than 1,350 people, the best gap was about 20–40% of the time to a test 1 week away and 5–10% for a test 1 year away.2

How many days should I wait before reviewing?

For an exam a week away, roughly 1.5 to 3 days: 20–40% of 7 days is 1.4 to 2.8 days. For exams further away, wait longer in days, but a smaller share of the time left.2

What is active recall and spaced repetition?

Active recall means testing yourself from memory instead of rereading; spaced repetition means doing that again after gaps. A major review rated these two, practice testing and distributed practice, the most useful study techniques.3,6

Is spaced repetition better than cramming?

For remembering on a test days or weeks away, yes. Across hundreds of experiments, spaced study beat the same amount of study in one block; cramming only wins when the test comes straight after studying.1,6

How many times should you review before an exam?

At least once, spaced out: the first self-test brings most of the benefit. Extra tests still add some, with diminishing returns.6

Should I keep reviewing flashcards I already know?

Yes. In a vocabulary experiment, words that kept being tested after the first correct recall were remembered much better later, while extra study of them did nothing.5

Sources

  1. Cepeda NJ, Pashler H, Vul E, Wixted JT, Rohrer D. Distributed practice in verbal recall tasks: A review and quantitative synthesis. Psychological Bulletin, 2006. Meta-analysis. doi.org/10.1037/0033-2909.132.3.354
  2. Cepeda NJ, Vul E, Rohrer D, Wixted JT, Pashler H. Spacing effects in learning: A temporal ridgeline of optimal retention. Psychological Science, 2008. Randomised trial. doi.org/10.1111/j.1467-9280.2008.02209.x
  3. Dunlosky J, Rawson KA, Marsh EJ, Nathan MJ, Willingham DT. Improving students' learning with effective learning techniques: Promising directions from cognitive and educational psychology. Psychological Science in the Public Interest, 2013. Review. doi.org/10.1177/1529100612453266
  4. Roediger HL, Karpicke JD. Test-enhanced learning: Taking memory tests improves long-term retention. Psychological Science, 2006. Randomised trial. doi.org/10.1111/j.1467-9280.2006.01693.x
  5. Karpicke JD, Roediger HL. The critical importance of retrieval for learning. Science, 2008. Randomised trial. doi.org/10.1126/science.1152408
  6. Fraundorf SH, Caddick ZA, Nokes-Malach TJ, Rottman BM. Cognitive perspectives on maintaining physicians' medical expertise: IV. Best practices and open questions in using testing to enhance learning and retention. Cognitive Research: Principles and Implications, 2023. Review. doi.org/10.1186/s41235-023-00508-8
  7. Martinengo L, Ng MSP, Ng TDR, Ang YI, Jabir AI, Kyaw BM, Tudor Car L. Spaced digital education for health professionals: systematic review and meta-analysis. Journal of Medical Internet Research, 2024. Meta-analysis. doi.org/10.2196/57760

The Exam Week Kit turns this into a plan: the revision methods with the strongest evidence (testing yourself, spacing, mixing problem types), a four-week countdown timetable, a daily revision structure, sleep, naps and caffeine limits for exam season, three tested tools for exam nerves, an exam-day checklist and printable planners. It also includes the Deep Sleep Protocol and the Focus & Flow State Protocol. The Exam Week Kit · Focus & Flow State Protocol

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