Anki

Anki is the open-source flashcard app that serious memorizers standardize on. Created by Damien Elmes in 2006, it schedules reviews with spaced repetition: each card reappears just before you would forget it, stretching intervals from minutes to months as material sticks. Recent versions ship FSRS (Free Spaced Repetition Scheduler), a machine-learning model trained on hundreds of millions of real reviews that predicts your personal forgetting curve — measurably more efficient than the older SM-2 algorithm and than the schedulers in Quizlet or Brainscape.

Its cultural stronghold is medical school. Community-maintained decks like AnKing (30,000+ cards mapped to USMLE Step 1 and 2) are near-universal among US med students, and language learners lean on shared decks for Japanese, Chinese, and vocabulary frequency lists. Cards support images, audio, video, LaTeX math, cloze deletions, and — now built in — image occlusion, where you hide labels on an anatomy diagram and reveal them one by one.

The trade-off is polish. Anki looks utilitarian, and options like leech thresholds and daily limits confuse beginners. The payoff is control: 1,500+ add-ons, custom card templates in HTML/CSS, and full ownership of your data.

Key Features

• FSRS scheduler that adapts intervals to your personal forgetting curve
• Cards with images, audio, video, LaTeX, cloze deletions, and image occlusion
• AnkiWeb sync across Windows, Mac, Linux, Android, iOS, and browser
• Thousands of shared community decks, including AnKing for med school
• 1,500+ add-ons — heatmaps, custom schedulers, AI card generators
• Fully customizable card templates using HTML and CSS
• Detailed statistics on retention, workload, and review history

Pricing

• Free: Desktop apps, AnkiWeb browser version, Android app (AnkiDroid), and syncing
• AnkiMobile (iOS, $24.99 one-time): The official iPhone/iPad app; purchases fund development

Best For

Medical students, law students, and language learners memorizing thousands of facts over months or years, plus anyone willing to trade an evening of setup for the most effective retention system available.

Limitations

Expect a learning curve — deck options, note types, and add-on installs are not beginner-friendly, and the interface feels a decade old. There is no native AI generation of cards from notes; tools like Brainscape or Quizlet do that out of the box. Casual studiers cramming for one quiz will find Anki overkill.