Anki
Powerful flashcard program
Anki — Official Website
Quick Take: Anki
Anki is the most powerful spaced repetition tool available. Nothing else matches its combination of algorithm quality (FSRS), customization (HTML/CSS templates), community (thousands of shared decks), and platform support (free on most platforms). The interface is ugly and the learning curve is steep, but the effectiveness is proven by millions of users—medical students, language learners, and professionals worldwide. If you need to memorize large amounts of information over months or years, Anki is the gold standard.
Best For
- •Medical students preparing for board exams
- •Language learners building vocabulary
- •Anyone who needs to memorize large amounts of factual information
- •Lifelong learners who want to retain what they read
What is Anki?
Anki is a free, open-source flashcard program that uses spaced repetition to help you remember things long-term. The core idea is simple: Anki shows you a flashcard, you rate how well you remembered it (Again, Hard, Good, Easy), and Anki schedules the next review based on your rating. Cards you know well appear less frequently. Cards you struggle with appear more often. Over time, this algorithm (based on SM-2, later replaced with FSRS in newer versions) moves knowledge into long-term memory with the minimum number of reviews. Anki was created in 2006 by Damien Elmes and has become the dominant spaced repetition tool worldwide. Medical students use it to memorize anatomy, pharmacology, and pathology. Language learners use it for vocabulary acquisition. Law students use it for case law. Software developers use it for API references and algorithm patterns. Anyone who needs to remember large amounts of factual information uses Anki. The app is free on macOS, Windows, Linux, and Android. The iOS version (AnkiMobile) costs $24.99—the revenue from this supports the project's development. Syncing between devices uses AnkiWeb, a free cloud service. Create cards on your Mac, review on your phone during your commute, and everything stays in sync. Anki's power comes from its flexibility. You can create simple text flashcards, cards with images, audio, cloze deletions (fill-in-the-blank), and complex layouts using HTML/CSS templates. The community has created thousands of shared decks covering medical boards (AnKing), language learning (Core 2k/6k Japanese), and programming concepts. You can download a pre-made deck and start reviewing immediately, or build your own from scratch. The learning curve is real. Anki's interface is functional but not pretty. The settings are numerous and confusing for beginners. But once you understand the basics—create cards, review daily, trust the algorithm—Anki becomes an indispensable tool for any knowledge-heavy pursuit.
Install with Homebrew
brew install --cask ankiDeep Dive: How Spaced Repetition Works and Why It Matters
Spaced repetition is based on the forgetting curve—a well-established phenomenon in cognitive psychology.
History & Background
Hermann Ebbinghaus discovered the forgetting curve in 1885: after learning something, memory decays exponentially unless reinforced. Piotr Wozniak developed the first practical spaced repetition algorithm (SM-2) in 1987, implemented in his software SuperMemo. Anki adopted SM-2 in 2006 and has since evolved to FSRS, a machine-learning-based algorithm that adapts to individual memory patterns.
How It Works
FSRS models each card's memory state using three parameters: stability (how long until the memory decays to 90% retention), difficulty (how hard the card is for this specific user), and elapsed days since last review. After each review, FSRS updates these parameters and calculates the optimal next review date. The model is trained on millions of reviews from opt-in users, then personalized to your individual data using the 'Optimize' button.
Ecosystem & Integrations
Anki's ecosystem includes AnkiWeb (free sync and review), AnkiMobile (iOS, $24.99), AnkiDroid (Android, free and open-source), and hundreds of add-ons. The shared deck library hosts thousands of decks. Communities like AnKing maintain high-quality decks with continuous updates. Competing products (Mochi, RemNote, Quizlet) offer better interfaces but weaker algorithms and smaller ecosystems.
Future Development
Anki development continues with FSRS improvements, better sync conflict resolution, and interface modernization. The FSRS algorithm is actively researched by the open-source community, with regular improvements to scheduling accuracy.
Key Features
Spaced Repetition Algorithm (FSRS)
Anki uses FSRS (Free Spaced Repetition Scheduler) in recent versions, replacing the older SM-2 algorithm. FSRS adapts to your individual memory patterns—it learns how quickly you forget and optimizes review intervals accordingly. Cards you know well might not appear for months. Cards you're learning might appear daily. The result is efficient memorization: maximum retention with minimum time reviewing.
Custom Card Templates
Cards are built with HTML/CSS templates, giving you complete control over appearance and behavior. Create basic front/back cards, cloze deletions (fill-in-the-blank), cards with images and audio, or complex multi-field layouts. Power users create cards with embedded diagrams, syntax-highlighted code blocks, and conditional fields. The template system is more powerful than any other flashcard app.
Shared Decks
AnkiWeb hosts thousands of free shared decks created by the community. Medical students download the AnKing deck (40,000+ cards covering USMLE Step 1 and Step 2). Language learners download Core vocabulary decks. Programming learners download algorithm decks. Shared decks give you a running start—you can review immediately without creating a single card yourself.
Cross-Platform Sync via AnkiWeb
Create cards on your Mac, review on your phone, check statistics on the web. AnkiWeb syncs your decks, progress, and review history across all devices for free. The sync is fast and conflict-resistant—you can review on multiple devices without losing progress.
Add-on Ecosystem
Anki supports add-ons (plugins) written in Python that extend its functionality. Popular add-ons include: Image Occlusion (create cards by hiding parts of an image), Review Heatmap (visualize your review streaks), Special Fields (protect certain fields during deck updates), and FSRS Helper (optimize algorithm parameters). There are hundreds of add-ons available.
Cloze Deletions
Cloze deletions turn a sentence into a fill-in-the-blank card: 'The mitochondria is the {{c1::powerhouse}} of the cell.' When reviewing, you see the sentence with a blank and try to recall the hidden word. This is more effective than basic front/back cards for contextual knowledge because you're recalling within context.
Media Support
Embed images, audio files, and video in your cards. Medical students include anatomical diagrams. Language learners include native speaker pronunciation audio. Music students include sound clips. Media is synced across devices through AnkiWeb.
Statistics and Review Tracking
Anki tracks everything: reviews per day, time spent reviewing, retention rate, cards learned vs. matured, forecast of upcoming reviews. The statistics help you understand your learning patterns and identify weak areas. The review heatmap (via add-on) visualizes your daily streaks.
Who Should Use Anki?
1The Medical Student
You're studying for USMLE Step 1. You download the AnKing deck (40,000+ cards covering pathology, pharmacology, anatomy, physiology, and biochemistry). You unsuspend cards as you cover each topic in lectures. You review 200-400 cards daily. Over two years, the spaced repetition algorithm moves thousands of facts into long-term memory. On exam day, you recall details you studied 18 months ago because the algorithm kept them fresh.
2The Language Learner
You're learning Japanese. You download a Core 2000 vocabulary deck with audio from native speakers. You learn 15 new words daily and review 50-80 cards. Each card has the Japanese word, reading, English meaning, and an example sentence. After 6 months, you've acquired 2,000+ words with minimal daily time investment. The spaced repetition ensures you don't forget words you learned early on.
3The Software Developer
You keep forgetting Git commands, SQL syntax, and Kubernetes kubectl options. You create cards for the commands you use but can't remember: 'git rebase -i HEAD~3', 'kubectl get pods -n namespace', 'SELECT ... GROUP BY ... HAVING'. You review 20 cards during your morning coffee. After a month, the commands are automatic.
4The Law Student
You need to memorize case holdings, legal rules, and statutory provisions for bar exam preparation. You create cloze deletion cards from your outlines: 'Under the dormant commerce clause, a state law is invalid if it {{c1::discriminates against}} or {{c2::unduly burdens}} interstate commerce.' Daily review keeps hundreds of rules accessible for exam day.
5The Lifelong Learner
You read books and articles but forget what you learned within weeks. You create Anki cards from key takeaways of everything you read. After a year, you have 3,000 cards covering history, science, philosophy, and technology. You review 50 cards daily in 10 minutes. You retain far more from your reading than you did before Anki.
How to Install Anki on Mac
Anki is available via Homebrew or direct download.
Install via Homebrew
Run `brew install --cask anki` in Terminal.
Create an AnkiWeb Account
Visit ankiweb.net and create a free account. This enables syncing between devices.
Download or Create Your First Deck
Browse shared decks at ankiweb.net/shared/decks or create your own deck with File → New Deck. Add cards with the Add button (Cmd+N).
Start Reviewing
Click on a deck and press 'Study Now'. Rate each card: Again (1 min), Hard (6 min), Good (10 min), or Easy (4 days). The intervals increase as you demonstrate knowledge.
Pro Tips
- • Start with 10-20 new cards per day. Going higher leads to overwhelming review backlogs.
- • Review every single day. Skipping days creates a backlog that's painful to clear.
- • Install the FSRS4Anki add-on and optimize parameters for your learning data—it significantly improves scheduling accuracy.
Configuration Tips
Keep New Cards to 10-20 Per Day
New users often set new cards to 50+ per day, creating massive review backlogs within a week. Start with 10-15 new cards daily. You can always increase later. The daily review count (new + review cards) should stay under 200 to avoid burnout.
Enable FSRS in Deck Options
In Deck Options, switch to the FSRS scheduler and click 'Optimize'. FSRS learns from your review history to create personalized intervals. It's significantly better than the default SM-2 algorithm for most users.
Use Cloze Deletions for Most Cards
Cloze deletions are more effective than basic front/back cards for most factual information. They provide context clues and test recall within a sentence. 'The {{c1::sympathetic}} nervous system increases heart rate' is better than 'What increases heart rate? / Sympathetic nervous system.'
Review at the Same Time Every Day
Build a habit by reviewing at a consistent time—during morning coffee, on your commute, or before bed. Consistency matters more than duration. 15 minutes daily beats 2 hours every weekend.
Alternatives to Anki
Spaced repetition has several options with different trade-offs:
Mochi
Mochi combines Markdown note-taking with spaced repetition flashcards. The interface is much prettier than Anki's. It lacks Anki's card template flexibility, add-on ecosystem, and shared deck library. Good for people who want SRS integrated with notes.
RemNote
RemNote combines an outliner note-taking tool with automatic flashcard generation. Type your notes and RemNote creates cards from them. Less flexible than Anki for pure flashcard use, but better for people who want notes and flashcards in one app.
Quizlet
Quizlet is simpler and prettier than Anki but uses a basic review algorithm, not true spaced repetition. Fine for short-term study (exam next week), inadequate for long-term retention. Anki is better for anyone studying over months or years.
Memrise
Memrise focuses on language learning with courses and spaced repetition. More polished than Anki for languages specifically, but less flexible for other subjects. Anki covers everything; Memrise is language-only.
Pricing
Anki is free on macOS, Windows, Linux, and Android. The iOS app (AnkiMobile) costs $24.99—this is a one-time purchase that supports the project's ongoing development. AnkiWeb (syncing and review via browser) is free. There are no subscriptions, no premium tiers, and no ads.
Pros
- ✓The most effective spaced repetition algorithm available (FSRS)
- ✓Free on macOS, Windows, Linux, and Android
- ✓Massive library of shared decks for medicine, languages, programming, and more
- ✓Unlimited customization via HTML/CSS card templates
- ✓Add-on ecosystem extends functionality significantly
- ✓Cross-platform sync via AnkiWeb
- ✓Proven by millions of users over 20 years
- ✓Open-source with active development
Cons
- ✗Interface is functional but dated—steep learning curve for beginners
- ✗Settings are numerous and confusing (learning steps, intervals, ease factors)
- ✗iOS app costs $24.99
- ✗Creating good cards takes practice—poorly made cards waste time
- ✗Daily review requirement can feel like a chore
- ✗Syncing occasionally conflicts when editing on multiple devices simultaneously
Community & Ecosystem
Anki has one of the largest and most active communities of any study tool. The r/Anki subreddit has nearly 200,000 members. Medical student communities (r/medicalschool, r/Step1) treat Anki as essential study infrastructure. The AnKing project maintains the most popular medical deck with continuous updates. Language learning communities share optimized decks for dozens of languages. The Anki add-on ecosystem has hundreds of plugins extending functionality. The developer, Damien Elmes, continues to maintain the project actively, with recent major additions including the FSRS algorithm and improved syncing.
Video Tutorials
Getting Started with Anki
More Tutorials
How To Effectively Use Anki
Evolving Medic, MD • 344.9K views
ANKI BASICS to crush med school 🔥
Claudia Green • 83.8K views
How To Use Anki Like A Pro: Full Step-by-Step Walkthrough
Alec Palmerton, MD • 22.5K views
Frequently Asked Questions about Anki
Our Verdict
Anki is the most powerful spaced repetition tool available. Nothing else matches its combination of algorithm quality (FSRS), customization (HTML/CSS templates), community (thousands of shared decks), and platform support (free on most platforms). The interface is ugly and the learning curve is steep, but the effectiveness is proven by millions of users—medical students, language learners, and professionals worldwide. If you need to memorize large amounts of information over months or years, Anki is the gold standard.
About the Author
Productivity & Workflow Analyst
Related Technologies & Concepts
Related Topics
Sources & References
Key Verified Facts
- Official website confirming Anki is a free, cross-platform flashcard program designed to greatly decrease time spent studying or greatly increase the amount learned.[cite-1]
- Official documentation explaining the core mechanics of Anki, including how spaced repetition works and the user rating system (Again, Hard, Good, Easy).[cite-2]
- Official documentation detailing the integration of the Free Spaced Repetition Scheduler (FSRS) as a modern replacement for the legacy SM-2 algorithm.[cite-3]
- The official open-source GitHub repository for the Anki desktop client, verifying its open-source status and active development in Rust and Python.[cite-4]
- The GitHub repository for the FSRS algorithm, demonstrating the open-source community's development of the advanced scheduling algorithm used in newer Anki versions.[cite-5]
- 1Anki - powerful, intelligent flashcards
Accessed May 6, 2026
"Official website confirming Anki is a free, cross-platform flashcard program designed to greatly decrease time spent studying or greatly increase the amount learned."
- 2Background - Anki Manual
Accessed May 6, 2026
"Official documentation explaining the core mechanics of Anki, including how spaced repetition works and the user rating system (Again, Hard, Good, Easy)."
- 3Deck Options - Anki Manual (FSRS)
Accessed May 6, 2026
"Official documentation detailing the integration of the Free Spaced Repetition Scheduler (FSRS) as a modern replacement for the legacy SM-2 algorithm."
- 4ankitects/anki: Anki's shared backend and Mac/Linux desktop code
Accessed May 6, 2026
"The official open-source GitHub repository for the Anki desktop client, verifying its open-source status and active development in Rust and Python."
- 5open-spaced-repetition/fsrs4anki
Accessed May 6, 2026
"The GitHub repository for the FSRS algorithm, demonstrating the open-source community's development of the advanced scheduling algorithm used in newer Anki versions."
- 6Learn Any Language Easily With Anki
Accessed May 6, 2026
"A Lifehacker publication highlighting how Anki utilizes spaced repetition to help users efficiently memorize vocabulary and shift it into long-term memory."
- 7Everything You Thought You Knew About Learning Is Wrong
Accessed May 6, 2026
"A Wired article covering the history of spaced repetition, the forgetting curve, and the underlying principles of the SM-2 algorithm used by digital flashcard systems."
- 8The best apps for students
Accessed May 6, 2026
"The Verge recommends Anki as a top study application, citing its highly customizable flashcards and powerful spaced repetition scheduling."
- 9FSRS Benchmark - Open Spaced Repetition
Accessed May 6, 2026
"Empirical benchmark repository comparing the FSRS algorithm against SM-2, showing significant data-backed improvements in memory retention efficiency."
- 10Spaced Repetition for Efficient Learning
Accessed May 6, 2026
"A comprehensive research analysis and benchmark of spaced repetition software, detailing the mathematical efficacy of Anki's scheduling algorithms in moving knowledge to long-term memory."