Frequently Asked Questions

The Leitner system is a spaced repetition method that uses physical boxes to schedule flashcard reviews. Cards are sorted into numbered boxes based on how well you know them. You review Box 1 every day, and move correct cards to higher-numbered boxes with longer review intervals. Cards you get wrong go back to Box 1. Once a card reaches the last box, it’s considered learned.

Three boxes is the right starting point for most people. A 3-box system is easy to set up and maintain, and it’s enough to see the benefit of spaced repetition. Start with three, build the habit, and expand to five or seven boxes after 4–6 weeks if you want longer intervals for more advanced cards.

No. The Leitner system was designed for physical index cards and boxes — no software required. All you need are cards, boxes or envelopes, a pen, and a schedule. The free printable downloads on this site give you everything you need to get started.

Start with a maximum of 5–10 new cards per day. This seems slow, but it keeps your Box 1 manageable. Adding too many cards at once is the most common reason Leitner systems collapse — Box 1 overflows, reviews take too long, and the habit breaks. See the guide on sustainable card limits for more detail.

It goes back to Box 1, regardless of which box it came from. A card in Box 4 that you get wrong goes all the way back to Box 1. This sounds harsh but it’s the mechanism that makes spaced repetition work — you only keep a card in a higher box if you can reliably recall it.

10–20 minutes for most people with a healthy system (Box 1 under 30 cards). If your daily review is consistently taking more than 30 minutes, your Box 1 is too full and you need to pause adding new cards. The Daily Review Routine Card walks through a structured 20-minute session.

Yes. The Leitner system works for any subject where you need to recall specific facts: languages, medicine, law, coding, music theory, history, science, maths. The key is writing good flashcards for your subject — the guides on this site cover language, maths, coding, and more.

Just resume where you left off. Missing one day won’t break the system — your cards will still be there. If you’ve missed several days and Box 1 is very large, spend a couple of days clearing Box 1 before resuming normal reviews. See the full missed day recovery guide.

When a card reaches your final box (Box 3, Box 5, or Box 7 depending on your setup), it’s considered learned. You can either retire it to an archive box or continue reviewing it at very long intervals (monthly). See the guide on retiring cards.

It depends on what you value. Anki uses a more sophisticated algorithm (SM-2) that automatically adjusts intervals based on your performance. The Leitner system uses fixed intervals that you control. Leitner is simpler, more transparent, and works without a device. Anki is more automated and better suited for very large decks (thousands of cards). For most learners with 100–500 cards, the Leitner system works just as well and requires less setup.

Spaced repetition is the practice of reviewing information at increasing intervals over time. Instead of reviewing everything every day, you review items right before you’re about to forget them. The Leitner system is one of the earliest and simplest implementations of spaced repetition — using physical boxes to manually track intervals. See the plain English guide to spaced repetition.

The most important rule: one fact per card. Front: a specific question. Back: a short answer (1–5 words, ideally). Avoid putting lists, long explanations, or multiple concepts on a single card. If a card keeps failing, it’s almost always a card quality problem rather than a memory problem. Download the Flashcard Quality Checklist for a full 8-point check.

The Leitner OS Dashboard is a Google Sheet that tracks your physical Leitner system. It automatically lists cards due for review, counts cards in each box, flags overdue cards, and shows which cards you keep getting wrong so you can rewrite them. It’s a one-time purchase with no subscription. See the full details.

This site is focused specifically on the Leitner box method. We don’t cover every study technique under the sun — just the Leitner system, spaced repetition, and flashcard writing. Everything is practical and printable. No filler, no academic jargon, no selling you on a productivity method. The goal is a working Leitner system on your desk by the end of the day you find this site.

Yes. The underlying principle — spaced repetition — is one of the most well-researched phenomena in cognitive psychology. The “spacing effect” has been studied since the late 19th century and has been replicated hundreds of times. Sebastian Leitner’s specific system (the box method) is a practical application of this research. Educational content on this site is based on publicly available research; we don’t make specific learning outcome guarantees.