Spaced Repetition Leitner System: How to Set Up Your Boxes
The spaced repetition Leitner system is a box method for flashcards. You keep your cards in a row of boxes, usually five, and every card starts in box 1. When you answer a card correctly, it moves up one box and gets reviewed less often. When you miss it, it goes back to box 1. Cards you know fade into the background, and cards you struggle with keep coming back.
Most people who study with flashcards fall into one of two traps. They reread the whole deck every day, which burns time on cards they already know. Or they cram before a test and lose most of it within a week. Both problems come from the same gap: no schedule that responds to what you actually remember.
This guide walks you through the Leitner box method in four steps: build the boxes, run a session, set the review schedule, and adjust as you go. It ends with how the method compares with apps like Anki, and where a manual box stops working. That last point matters to us at MemoRep, because we apply the same spaced repetition idea to practicing songs and exercises rather than flashcards.
Why the Leitner system works
What the system does
The Leitner system is a flashcard sorting method that turns spaced repetition into a physical routine. Science journalist Sebastian Leitner popularized it in the 1970s, and it survives because it needs nothing but cards and boxes.
Spaced repetition means you review something just before you would forget it, then wait longer each time. Memory drops fast after first exposure, a pattern known as the Ebbinghaus forgetting curve, and each successful recall slows the next drop. Published work on optimizing spaced repetition schedules describes the technique the same way: repeated review of content on a schedule. In the Leitner system, the box number is the schedule.
The box number is the interval: the higher the box, the longer a card waits.
What you need before you start
Gather these items first. The whole kit costs very little.
- 50 to 100 index cards, or any stiff paper cut to card size
- Five containers, or one shoebox with four dividers
- A marker to label boxes 1 to 5
- A daily slot of 10 to 20 minutes, at the same time each day
Step 1. Build your boxes and write your cards
Set up five boxes
Label the boxes 1 through 5 and line them up in order. Five boxes is the standard layout, and it gives you enough room for cards to climb from "new" to "well known." Put every new card in box 1. Nothing starts higher, no matter how easy it looks.
Write cards that test one thing
Put a prompt on the front and a short answer on the back. One fact per card keeps your answers clean, because a card with three parts forces you to mark it wrong when you know two of them. Write in your own words where you can, since the effort of phrasing it helps you remember it.
Start with 10 to 20 cards, not 200. A huge first batch floods box 1 and makes your first week feel like a chore.
One fact per card keeps every right or wrong verdict honest.
Step 2. Run a review session
Follow the sorting rule
Each session follows one rule: right goes up, wrong goes down. Work through it like this:
- Pull the cards that are due today (the next step explains which boxes).
- Read the front and say your answer out loud or in your head before you flip the card.
- If you were right, move the card up one box.
- If you were wrong, even slightly, move it back to box 1.
- If a card in box 5 is right, it is learned. Retire it, or keep it in box 5 for an occasional check.
Work through box 1 first
Start with box 1. New and struggling cards need your freshest attention, and you want them out of the way before your focus fades. Shuffle each box before you start so you do not learn the order instead of the answers.
Be strict about the "wrong" verdict. If you hesitated for ten seconds and then guessed, treat the card as missed. Honest grading is what makes the intervals work.
If you had to guess, the card goes back to box 1.
Step 3. Set your review schedule
Pick an interval for each box
The simplest schedule doubles the wait for each box. Count your study days from 1, and review a box on any day divisible by its interval.
| Box | Review every | Review on days |
|---|---|---|
| 1 | Day | Every day |
| 2 | 2 days | 2, 4, 6, 8... |
| 3 | 4 days | 4, 8, 12... |
| 4 | 8 days | 8, 16, 24... |
| 5 | 16 days | 16, 32, 48... |
Guides differ here. Some use 1, 3, 7, 14 and 30 days instead. Doubling is easy to track, and you can stretch the later boxes if you find them too frequent.
Work through a two-day example
Say you add 10 new cards per day. On day 1, you review 10 cards in box 1. You get 8 right, so they move to box 2, and the other 2 stay in box 1.
On day 2, you add 10 new cards, so box 1 holds 12. Day 2 is also a box 2 day, so those 8 cards are due. Your day 2 session is 20 cards. The load grows for the first couple of weeks, then levels off as cards move into the slow boxes. If sessions pass 20 minutes, cut new cards to 5 a day.
Doubling the interval at each box gives you a schedule you can run without a calendar.
Step 4. Adjust the system and know its limits
Fix the common problems
Most problems show up as a swollen box 1. That usually means too many new cards or cards that test too much at once. Split vague cards into smaller ones and slow your intake.
If you skip a day, do not try to catch up on everything. Resume on the next day number and review whatever is due. After a long break, start with box 1 and the lowest due boxes, and let the system sort itself out.
Compare Leitner with an app
A paper box and an app solve the same problem with different trade-offs.
| Leitner box | Spaced repetition app (such as Anki) | |
|---|---|---|
| Cost | A few dollars of supplies | Varies by app |
| Scheduling | Fixed interval per box | Interval calculated per card |
| Tracking | You do it by hand | Automatic |
| Best for | Simple fact decks, a tactile routine | Large decks, hands-off scheduling |
Anki's scheduler descends from the SuperMemo SM-2 algorithm, which adjusts each card's interval based on how hard it felt. Leitner is simpler, apps are more precise.
Both are built for facts with a front and a back. A song, an exercise, or a skill you perform has no flip side. That is why MemoRep exists. It uses SM-2-style scheduling for practice cards, and you rate each pass as Again, Hard, Good, or Easy so the next session lands when the skill is about to fade.
A box schedules facts, and a practice app schedules skills you perform.
Putting your boxes to work
The Leitner system comes down to one rule and one schedule. Right answers move a card up and wrong answers send it to box 1, while each box has a longer wait than the one before. Build five boxes, write short single-fact cards, grade yourself honestly, and review on a doubling schedule. Start small, and let the load level off by itself.
If your goal is practicing music or another practical skill, the same logic applies, but the cards are songs and exercises instead of facts. You can try MemoRep during the free beta and let it decide what to practice next and when.
