About
spacedrepetition.info explains how spaced repetition works and describes the apps that use it. It aims to be a clear, accurate reference for students and anyone who wants to remember what they learn.
What does the site cover?
The site has four parts:
- Learn: the research on memory and study, from the forgetting curve to active recall.
- Algorithms: how SM-2, FSRS, the Leitner system and SuperMemo decide when you review.
- Apps: profiles of flashcard apps, with their price, platforms and scheduling.
- Glossary: plain definitions of the terms used across the site.
How are the articles written?
Every article is researched from primary sources: peer-reviewed studies, meta-analyses and official documentation. The main claims are marked with a number that links to the full reference at the end of the article. When the evidence is mixed or thin, the article says so.
Each article shows the date it was last updated.
How are the apps profiled?
App profiles are built from each app's official website, documentation and store listings, and checked in the app itself. Each profile shows the date its facts were last checked, since prices and features change.
Apps are not scored or ranked. A missing feature is described as not offered, not as a lower grade, and each profile ends with a short review of who the app suits.
How can you report an error?
If you spot a mistake or an outdated fact, write to contact@spacedrepetition.info. Corrections are made as quickly as possible.