# The Leitner method: a complete guide to mastering your flashcards
Flashcards are everywhere. But most students use them wrong. They create a deck of 200 cards, go through them once, then forget them in a drawer. Or worse: they review the same cards in the same order, day after day, with no strategy. The result? Hours of work for a médiocre rétention rate.
In 1972, German science journalist Sebastian Leitner proposed an elegant solution to this problem. His system, based on five boxes and simple movement rules, remains one of the most effective methods for turning flashcards into a long-term memorization tool.
This guide explains how the method works, why it works, and how to set it up --- with physical cards or with an app.
What is the Leitner system?
The Leitner system is a flashcard learning method that uses spaced répétition to strengthen memorization. The principle is simple: cards you have mastered are reviewed less often, while those that give you trouble come back more frequently.
The system relies on five boxes (or compartments), each associated with a different review frequency.
The 5 boxes and their intervals
- Box 1: review every day
- Box 2: review every 2 days
- Box 3: review every 4 days
- Box 4: review every week
- Box 5: review every 2 weeks
The movement rules
All cards start in Box 1. At each review session:
- Correct answer: the card moves to the next box (Box 1 to Box 2, Box 2 to Box 3, etc.)
- Incorrect answer: the card goes back to Box 1 immediately, regardless of its current level
A card in Box 5 that you answer correctly is considered mastered. You can remove it from the cycle or keep it for occasional reviews.
This mechanism creates a natural filter: difficult information is reviewed intensively, easy information less and less often. Your review time is invested where it matters most.
The science behind the method
The Leitner system combines two fundamental principles of cognitive psychology: spaced répétition and active recall.
Spaced répétition
The concept of spaced répétition dates back to Ebbinghaus's work on the forgetting curve (1885). In 2006, Cepeda and colleagues published a massive meta-analysis covering 254 studies, confirming that distributing learning over time significantly improves long-term rétention compared to cramming (Cepeda et al., 2006).
The Leitner system implements spaced repetition mechanically: the more a card is mastered, the longer the interval before the next review. This is exactly the optimal pattern identified by research. To learn more about spaced repetition, see our complete guide on spaced repetition.
Active recall
Every time you look at a card and try to remember the answer before flipping it, you are practicing active recall. Nate Kornell demonstrated in 2009 that simply attempting to retrieve information from memory --- even if you fail --- strengthens the memory trace more than passive rereading (Kornell, 2009).
It is the combination of thèse two mechanisms that makes the Leitner system so powerful: you practice active recall at optimal intervals.
Step by step: setting up Leitner with physical cards
Materials needed
- Index cards (A7 format or half A6 cards)
- 5 dividers or 5 small boxes (cut-up shoeboxes work fine)
- A marker to label the boxes
Creating cards
- One piece of information per card. Never put three definitions on the same card.
- Front: the question. Frame it as a real test. "What is the mitochondria?" is better than "Mitochondria."
- Back: the answer. Short, precise. If the answer exceeds 2-3 lines, split the card into multiple cards.
Review routine
- On the first day, all cards are in Box 1. Review them all.
- The next day, review Box 1 (incorrect cards from yesterday + new cards).
- Every 2 days, also review Box 2. Every 4 days, Box 3. And so on.
- Strictly apply the movement rules: correct answer = next box, incorrect answer = back to Box 1.
Practical tip
Note the review days for each box on a calendar. For example, if you start on a Monday: - Box 1: every day (Monday through Sunday) - Box 2: Wednesday, Friday, Sunday - Box 3: Thursday, the following Monday - Box 4: the following Monday - Box 5: every 2 weeks
Step by step: setting up Leitner digitally
Modern flashcard apps automate the Leitner system --- or more sophisticated variants --- so you no longer have to manage boxes manually.
Option 1: traditional flashcard apps
Apps like Anki, Quizlet, or Brainscape integrate forms of spaced repetition. You create your cards, and the algorithm decides when to present them. For a detailed comparison, see our Anki vs Quizlet vs Wizidoo comparison.
Option 2: automatic génération with AI
Creating hundreds of flashcards by hand is tedious --- and is often the reason students abandon the system. AI-based tools can automatically generate cards from your course materials.
Wizidoo applies Leitner-style spaced repetition automatically: weak concepts are reviewed more frequently, mastered ones are progressively archived. No manual box management. The AI generates flashcards and exercises directly from your course materials --- photos, PDFs, text. First course free. Available on iOS.
Common mistakes with flashcards
Even with the Leitner system, certain mistakes can ruin your efforts.
Creating too many cards at once
If you add 150 cards to Box 1 on the same day, your first session will be an exhausting marathon. Add 20 to 30 new cards per day maximum. Let the system absorb the load gradually.
Cards that are too vague
"Explain the French Revolution" is not a good flashcard. That is an essay topic. Prefer precise questions: "In what year did the storming of the Bastille take place?" or "What event marks the beginning of the French Revolution?" One card = one fact.
Ignoring the spacing
Reviewing all your cards every day, without respecting the box intervals, cancels out the system's advantage. The goal is to review at the right time, not all the time. If you review too early, you do not give forgetting enough time to do its consolidation work.
Never retiring cards
Cards you have mastered perfectly for weeks can leave the cycle. The Leitner system is not a life sentence. If a card has been in Box 5 for a month and you never hesitate, remove it.
Reading instead of testing
Looking at the back before attempting to answer mentally destroys the active recall effect. Force yourself to formulate the answer in your head --- or out loud --- before checking. For more on rapid memorization techniques, we have a dedicated guide.
Leitner vs algorithmic SRS (Anki): what are the differences?
The Leitner system and modern spaced répétition algorithms (like SM-2 used by Anki) share the same scientific foundation. But they differ in how they work.
Scheduling complexity
Leitner uses 5 fixed levels with predefined intervals. It is simple, predictable, and easy to understand. Anki's algorithm calculates a personalized interval for each card based on your response history, success rate, and an ease factor. It is more precise but less transparent.
Granularity
With Leitner, a response is binary: correct or incorrect. With Anki, you rate your response on a scale (Again, Hard, Good, Easy), which allows finer interval adjustments.
Flexibility
Leitner is rigid by design: 5 boxes, simple rules. Anki is highly configurable --- which is both an advantage and a trap. Many users spend more time configuring Anki than actually reviewing.
Verdict
For beginners or simple content (vocabulary, definitions, dates), Leitner is more than enough. For large card volumes or complex content (medicine, law), an SRS algorithm like Anki or Wizidoo offers measurable efficiency gains.
When does the Leitner method work best?
The Leitner system excels for factual knowledge: discrete, verifiable information with a single correct answer.
Ideal use cases
- Vocabulary (foreign languages): one word = one card
- Definitions (science, law, economics): one term = one définition
- Anatomy and pharmacology (medicine): one muscle = one insertion, one drug = one class
- Dates and events (history): one fact = one date
- Formulas (chemistry, physics): one formula = one application
When Leitner falls short
For understanding complex systems, problem-solving, or argumentation, flashcards alone are not enough. They are a complement, not a substitute for deep compréhension. A médical student who knows every arm muscle by heart but does not understand their biomechanical interaction has a problem Leitner will not solve.
The médical school case
Médical students are historically the biggest flashcard users. The volume of factual information to retain (anatomy, pharmacology, semiology) is enormous. The Leitner method, or its digital equivalents, is virtually indispensable in this context. Entire communities (AnkiMed, r/medicalschoolanki) are built around this approach.
FAQ
How many flashcards per session?
Between 20 and 50 cards per session is a good balance. Beyond 50, cognitive fatigue reduces recall quality. If your Box 1 contains more than 50 cards, split the session into two blocks spaced a few hours apart.
Should you write your own flashcards?
Yes, ideally. The creation process is itself a learning act: it forces you to reformulate, synthesize, and identify key points. However, for large volumes, using pre-made or AI-generated decks (then personalizing them) is a reasonable compromise.
Does the Leitner method work for math?
Partially. Flashcards work well for memorizing formulas, theorems, and definitions. But mathematics primarily requires problem-solving practice, which the question-answer format of a flashcard does not cover. Use Leitner for the factual layer, and complement with exercises.
What is the difference between Leitner and Anki's algorithm?
Leitner uses 5 fixed boxes with predefined intervals (1, 2, 4, 7, 14 days). Anki's SM-2 algorithm calculates a personalized interval for each card based on your past responses. Anki is more precise but more complex. Leitner is simpler and sufficient for the majority of use cases.
Can you use Leitner without an app?
Absolutely. The system was designed for physical cards. Five boxes, index cards, and a calendar are all you need. The advantage of paper: no digital distractions. The downside: manual interval management becomes tedious beyond a few hundred cards.
Sources: Leitner, S. (1972). So lernt man lernen. Herder. --- Cepeda, N. J. et al. (2006). Distributed practice in verbal recall tasks. Psychological Science, 17(9). --- Kornell, N. (2009). Optimising learning using flashcards. Applied Cognitive Psychology, 23(9).