• Leitner box

The Leitner box: spaced repetition you can do with a shoebox

Before there was software, there was a shoebox with dividers in it. The Leitner system is spaced repetition implemented in cardboard, invented in the 1970s, and it is still a completely legitimate way to study — particularly if your problem is that opening an app is how you end up on your phone for forty minutes.

Updated August 14, 20265 min readStudy technique

How it works

Five boxes. Every new card starts in box 1. When you get a card right, it moves up one box. When you get it wrong, it goes straight back to box 1 — no matter how far it had climbed. That demotion rule is the entire cleverness of the system.

Then you review each box on a different rhythm. Box 1 every day. Box 2 every other day. Box 3 twice a week. Box 4 weekly. Box 5 monthly. Cards you find easy climb quickly and stop bothering you; cards you keep failing sink back to box 1 and get drilled daily until they stick.

What it gets right

It's genuinely adaptive. Two cards diverge based on your performance — which is the thing most 'spaced repetition' apps do not actually do.
No screen. No notifications, no tabs, nothing to be nerd-sniped by.
It's tangible. Watching box 1 empty is more motivating than a number going down, for reasons nobody has fully explained.
Zero cost. Index cards and a shoebox.

What it gets wrong

The intervals are fixed by box, not fitted to your memory. A modern scheduler like FSRS models each card's stability and difficulty separately and picks a moment; Leitner just moves it to the next tier. For a few hundred cards the difference is small. For the four thousand cards of a medical degree, the difference is an hour a day.

And you still have to hand-write every card, which is the reason most people quit any spaced repetition system, in cardboard or otherwise.

Common questions

What is the Leitner system?

A physical spaced repetition method: cards move up a box when you get them right and fall back to box 1 when you get them wrong. Each box is reviewed on a longer rhythm than the last.

Is the Leitner box as good as Anki?

For small decks, close enough that it doesn't matter. For large decks, a real scheduler like FSRS is meaningfully more efficient because it fits intervals to each card rather than to a box tier.

How many boxes should I use?

Five is standard. More boxes give finer granularity and more admin; the point of the system is that it's simple enough that you'll actually do it.

Try it on your own material

Upload your notes, slides or lecture recordings and get a tutor that answers only from them — and says so when they don't cover it.

Get started See pricing

$12/month, or $8/month billed yearly · cancel in two clicks