The Leitner System: Flashcards That Actually Work

TL;DR. The Leitner System, invented by Sebastian Leitner in 1972, is a paper-based spaced repetition method. Cards live in 3–5 boxes; correct answers move up; failures move down. It's the analog ancestor of Anki and still works brilliantly.

How it works

Five boxes, each on a different review schedule:

| Box | Review every | Use case |

|---|---|---|

| 1 | Daily | New cards or recently failed |

| 2 | Every 2 days | First success |

| 3 | Every 4 days | Second success |

| 4 | Weekly | Third success |

| 5 | Monthly | Long-term review |

When you correctly recall a card, it moves up one box. When you fail, it drops to Box 1 regardless of which box it was in.

Setting it up

Question on one side, answer on the other.

Daily routine

Total: 15–25 min/day for a mature deck of 200–400 cards.

Why it works

The brain forgets on a curve; each retrieval flattens it. The genius of Leitner is that spacing *emerges automatically* from the box mechanic — hard cards get tested often, easy cards rarely.

When to use paper Leitner over an app

When to use an app

SimpleQuizMaker's flashcard mode uses the same Leitner-inspired logic with algorithmic scheduling.

A 30-day experiment

Pick a subject. Write 50 cards. Set up boxes. Run the daily routine for 30 days. Most learners report 80% durable retention at day 30.

Related reading

Try SimpleQuizMaker's flashcard mode →