Anki is a free and open-source flashcard program that utilizes spaced repetition. Spaced repetition has been shown to increase rate of memorization. "Anki" is the Japanese word for "memorization". The SM2 algorithm, created for SuperMemo in the late 1980s, forms the basis of the spaced repetition methods employed in the program. Anki's implementation of the algorithm has been modified to allow priorities on cards and to show flashcards in order of their urgency. The cards are presented using HTML and may include text, images, sounds, videos, and LaTeX equations. The decks of cards, along with the user's statistics, are stored in the open SQLite format.
Features
Syncing
Anki supports synchronization with a free online server called AnkiWeb. This allows users to keep decks synchronized across multiple computers, and to study online or on a cell phone. There is a third-party open source AnkiServer software which users can run on their own local computers or servers, though it is not compatible with recent Anki versions. It also provides a RESTful API for manipulating Anki collections.
Japanese and Chinese reading generation
Anki can automatically fill in the reading of Japanese and Chinese text. Since version 0.9.9.8.2, these features are in separate plug-ins.
Add-ons
More than 500 add-ons for Anki are available, often written by third-party developers. They provide support for speech synthesis, enhanced user statistics, image occlusion, incremental reading, allow for more efficient editing and creation of cards through batch editing, modify the GUI, simplify import of flashcards from other digital sources, add an element of gamification, etc.
Shared Decks
While Anki's user manual encourages the creation of one's own decks for most material, there is still a large and active database of Shared Decks that users can download and use. Available decks range from foreign language decks to geography, physics, biology, chemistry and more. Various medical science decks, often made by multiple users in collaboration, are also available.
Comparisons
Anki's scheduling algorithm is based on an older version of the SuperMemo algorithm. While pure SM2 recommends an interval of 1 day, then 6 days, however, Anki uses 1 day, then 3 days. The Anki author states that versions 3–5 of the SuperMemo algorithm are more susceptible to incorrect scheduling. The latest SuperMemo algorithm in 2019 is SM18. Some Anki users who experimented with algorithms and settings have published configuration recommendations, made add-ons to modify Anki's algorithm, or developed their own separate software.
Mobile versions
The following smartphone/tablet and Web clients are available as companions to the desktop version:
The flashcards and learning progress can be synchronized both ways with Anki using AnkiWeb. With AnkiDroid it is possible to have the flashcards read in several languages using text-to-speech. If a language does not exist in the Android TTS engine, a different TTS engine such as SVOX TTS Classic can be used.
History
The oldest mention of Anki that the developer, Damien Elmes, could find in 2011 was dated 5 October 2006, which was thus declared Anki's birthdate. In 2010, Roger Craig obtained the then-all-time record for single-day winnings on the quiz showJeopardy! after using Anki to memorize a vast number of facts. Version 2.0 was released on 6 October 2012. Version 2.1 was released on 6 August 2018.
Utility
While Anki may primarily be used for language learning or a classroom setting, many have reported other uses for Anki: scientist Michael Nielsen using it to remember complex topics in a fast-moving field, others using it to remember memorable quotes, the faces of business partners or medical residents, or remember business interviewing strategies.
Medical education
Anki is quickly becoming an important resource for many medical students in the US. A study in 2015 at Washington University School of Medicine found that 31% of students who responded to a medical education survey reported using Anki as a study resource. The same study found a positive relationship between the number of unique Anki cards studied and USMLE Step 1 scores in a multi-variate analysis. Some third-party resources, such as Boards and Beyond, have Anki decks based on them.
Copera Inc.'s Anki for Palm OS
An unrelated flashcard program called Anki for Palm OS was created by Copera, Inc. and released at the PalmSource conference in February 2002. Anki for Palm OS was sold from 2002 to 2006 as a commercial product. In late 2007, Copera, Inc. decided to release Anki for Palm OS as freeware.
