Leitner System Schedule for 3, 5 and 7 Boxes

Which box do you review today? On a Leitner schedule, you review Box 1 every day, and each higher box on a longer fixed gap. On any given day you open only the boxes whose turn has come.

The gaps themselves are not standardized. Different guides give different numbers for the same box count, and Sebastian Leitner's own method did not use a calendar at all. This page sets out the common 3, 5 and 7 box schedules side by side, gives you a 64-day calendar to copy, and shows how to choose a box count based on how far away your exam is.

Every card starts in Box 1. When you answer a card correctly, it moves up one box. When you miss it, it goes back to Box 1. The University of York's study guide puts it this way: correct cards "progress to boxes that you don't need to review as often, while incorrect ones are moved back to the first box."

The schedule adds one more rule: each box has a review interval, and the intervals grow as you move up. Cards you keep missing come up daily. Cards you know well come up rarely. Your study time goes where your memory is weakest.

The day counts came later. According to Wikipedia's summary, Leitner's 1972 book So lernt man lernen used physical partitions 1, 2, 5, 8 and 14 cm wide. You reviewed a section when it filled up. Calendar schedules are a modern convention, which is why the numbers vary from guide to guide.

Other versions differ at the top end. Wikipedia lists a 3-box variant reviewed daily, every 3 days and every 5 days. Another five-box version from ActiveRecalling's complete guide runs daily, every 3 days, weekly, every two weeks and monthly. FluentFlash gives Box 4 as every 9 to 10 days and Box 5 as every 2 to 4 weeks.

The pattern is the same in all of them. FluentFlash describes it as intervals that "approximately double with each box." No source shows that one exact set of numbers beats another. Pick one schedule and keep to it, rather than switching between them.

A fixed calendar is easier to follow than tracking a due date on every card. Number your study days from 1. On day N, review every box whose interval divides evenly into N. The days below use the 7-box intervals from Leitnerbox.io. For a 3 or 5 box system, use only the first rows. If you are setting up a physical box, put a date tab on each divider (how to make a Leitner box at home covers that build).

Here is how to read it. Day 28 means Boxes 1, 2, 3 and 4. Day 60 means Boxes 1, 2, 3 and 5. Day 63 means Boxes 1 and 4. After day 64, start again at day 1.

The simplest rule is not to build a box you will never open. If your exam is three weeks away, Box 6 and Box 7 never come up before test day. Any card that reaches them is just sitting idle. FluentFlash suggests three boxes for short-term study and five or more for retention over months. That matches the arithmetic: a 3-box weekly schedule cycles several times in a month, and the 64-day box only pays off if you need the material for months.

For exams far off, add boxes. For exams close by, cut them. If you are working toward a goal with no end date, such as a language or a licensing field, the seven-box version keeps your workload from growing without limit.

The research case for spacing is broad. The ActiveRecalling guide cites a Cepeda et al. (2006) meta-analysis of 254 studies with more than 14,000 participants showing that spaced practice beats massed practice for long-term retention. A 2008 Cepeda study is often cited for a more specific claim: that the best gap between reviews grows as the time until your test grows. That study is not among the sources we drew on here, so we won't give a figure for it. Read the box-count rule above as reasoning, not a measured optimum.

One concrete schedule has been tested directly. A 2025 study in Frontiers in Medicine gave 90 medical students reviews at 1, 3, 7, 14 and 28 days, close to a five-box ladder. The spaced group retained substantially more on post-tests than students who studied the conventional way. The study was quasi-experimental, not randomized, so treat it as support, not proof.

Apps like Anki set intervals card by card, based on your performance. A Leitner calendar gives every card in a box the same gap. In a 2019 PNAS study, Tabibian and colleagues tested scheduling methods on about 12 million Duolingo study sessions. They found that Leitner's exponential spacing is a special case of their more general model, and that their adaptive algorithm, MEMORIZE, produced lower forgetting rates than simpler schedules.

That makes a box calendar a reasonable heuristic, not the best schedule possible. What it gives you in return is something you can run with a shoebox and a pen, with no software involved.

Count the days to your exam, keep only the boxes whose interval fits inside that window, and write the day numbers on your dividers. Then judge yourself on practice-test scores, not on how sure you feel. In a 12-student radiology pilot and a microbiology course study, flashcard users gained confidence, but neither study found a significant improvement in test scores.