Spaced Repetition Flashcards - Online Leitner Box Method

The Leitner Box Method is a spaced repetition technique developed by Sebastian Leitner in the 1970s. Flashcards are sorted into boxes based on how well you know them. Cards in Box 1 are reviewed daily, while cards in higher boxes are reviewed less frequently. When you answer correctly, the card moves to the next box. If you forget, it goes back to Box 1. This ensures you spend more time on difficult material and less on material you've mastered.

Box 1: Reviewed daily — new and difficult cards live here.
Box 2: Reviewed every 2 days.
Box 3: Reviewed every 4 days.
Box 4: Reviewed every 7 days.
Box 5: Reviewed every 14 days — these are well-mastered cards.
When you get a card right, it advances one box. When you get it wrong, it returns to Box 1 regardless of where it was.

Spaced repetition leverages the spacing effect — a well-documented psychological phenomenon where information is better retained when learning sessions are spaced out over time. By reviewing material just before you're about to forget it, you strengthen neural connections and dramatically improve long-term retention. Studies show spaced repetition can improve recall by 200-300% compared to cramming.

All your flashcard data is stored locally in your browser using localStorage. This means your data never leaves your device and is completely private. However, clearing your browser data will delete your flashcards. We recommend regularly exporting your cards as a JSON backup file using the Export button.

Click the Export button to download all your flashcards as a JSON file. To restore or transfer cards, click Import and select the JSON file. The imported cards will be merged with your existing cards. This is perfect for backing up your progress or moving between devices.

• Keep it concise: One fact per card. Short questions work best.
• Use your own words: Self-generated content improves recall.
• Be honest: Only click "Remembered" if you truly recalled the answer.
• Review daily: Consistency is key. Even 5-10 minutes a day makes a huge difference.
• Mix subjects: Interleaving different topics improves overall learning.