What is Spaced Repetition Tool?

Spaced Repetition Tool uses the SM-2 algorithm to help you memorize anything. Create flashcards, review them on a smart schedule, and track your progress. Difficult cards show up more often, and cards you already know show up less, so you spend less time studying and remember more.

The scheduler runs SM-2 — the same algorithm Anki and SuperMemo grew up with. Each rating (Again, Hard, Good, Easy) updates the card's easiness factor and interval, so a card you nailed three times in a row might not show up again for a month. Decks live in your local storage and export as JSON for backup.

How to use

1. Create a deck and add flashcards with a front (question/term) and back (answer/definition).
2. Start a review session — cards due for review appear based on the SM-2 spaced repetition algorithm. Rate each card from 'Again' to 'Easy'.
3. Track your progress with statistics: cards learned, review accuracy, upcoming schedule. Export your decks as JSON for backup.

When to use

• Drilling foreign vocabulary you keep forgetting after one read-through.
• Memorising medical, legal, or anatomy terms for a closed-book exam.
• Locking in coding interview patterns or shortcut keys long enough to retrieve them under pressure.

Result

You're studying Spanish vocabulary. Create a deck, add 20 cards (e.g., front: 'house', back: 'la casa'). After the first review, easy cards won't appear for 4 days, while difficult ones return tomorrow.

FAQ

What is the SM-2 algorithm and why is it the standard for flashcards?

SM-2 is the spacing formula Piotr Wozniak published in 1987. It adjusts each card's review interval based on how well you recall it — easy cards stretch out exponentially, missed cards reset to a short interval. It's the basis for Anki and most modern SRS apps.

How do Again, Hard, Good, and Easy change my next review date?

Again resets the card to a one-minute interval. Hard lengthens it slightly. Good multiplies by the easiness factor (around 2.5x at first). Easy pushes the interval out by an additional 30%, so cards you find trivial stop crowding your queue.

Are my decks shared across devices?

No. Decks are saved in your browser's localStorage on this device. To move them to another machine, export the deck as JSON, then import it on the other device. There's no cloud sync, which keeps the data fully on your computer.

What's the difference between 'new cards' and 'due cards'?

New cards have never been reviewed — they show up immediately the first time you study. Due cards are ones the algorithm scheduled for today or earlier. Reviewing both keeps you learning new material while retaining old.

How many cards should I review in one session?

Most learners stick to 10–20 new cards a day plus whatever is due — usually 50–100 total. Going above that overloads short-term memory, and the next-day pile grows faster than you can keep up with.

Related Tools