Mora’s Spaced Repetition Algorithm Explained

Most flashcard apps use a standard spaced repetition algorithm (like SM-2, the one behind Anki). But when we started building Mora, we noticed something: those algorithms can feel too rigid and sometimes schedule reviews so far apart that you forget words before they come back.

That’s why we designed a custom spaced repetition system, tuned for real-world language learners.

How Mora’s Algorithm Works

Mora’s system has two phases:

1. Learning phase → for brand new or early cards.
2. Review phase → for cards that have already “graduated” into your long-term memory.

The way Mora grades your answers depends on the study mode:

• Typing mode → you type the answer, and Mora grades it as:
  • ✅ Perfect → exactly correct.
  • ✏️ Almost → a near miss (e.g., small typo).
  • ❌ Incorrect → wrong.
• Recall mode → you flip the card and self-grade:
  • ✅ Correct
  • ❌ Incorrect

This flexibility keeps the algorithm both accurate (with typing) and lightweight (with recall).

Learning Phase: Build a Strong Foundation

When you first learn a word, you need to see it often. Mora schedules reviews like this:

• 1st correct → 8 hours later
• 2nd correct → 1 day later
• 3rd correct → 2 days later → then it graduates into the Review phase

If you miss a card:

• Almost (typing mode only) → Mora repeats the step sooner (about half the time).
• Incorrect → The card resets to the beginning (8h).

Review Phase: Stretching Your Memory

Once a card has been recalled a few times, it enters the Review phase. Mora gradually increases the intervals:

• 4 days → 7 days → 14 days → 30 days → 60 days → 120 days

After that, intervals grow using a multiplier based on how easy the card has been for you (your “easiness factor”). This keeps practice efficient without overwhelming you.

If you struggle:

• Almost (typing mode only) → the card stays at the same step and comes back sooner.
• Incorrect → early cards go back to the Learning phase; mature cards get pulled much closer for a refresher.

Why Mora’s System Feels Different

• Gentler on beginners → Early reviews are closer together, so new words don’t slip through the cracks.
• Mode-aware grading → Typing mode uses fine-grained feedback, while recall mode stays simple with correct/incorrect.
• Natural spacing → Mora adds a little randomness (±10%) so you don’t get overwhelmed by too many cards at once.

Why Not Just Use SM-2?

The SM-2 algorithm (used by Anki and SuperMemo) is powerful, but it was designed decades ago and can sometimes feel too aggressive. With SM-2, you might not see a card for weeks after just a couple of successes — only to forget it completely.

Mora takes the same science of spaced repetition, but tunes it to be more forgiving and practical for daily language learning.

Final Thoughts

Spaced repetition doesn’t have to be intimidating or complicated. Mora handles the scheduling automatically — all you need to do is show up and study.

That’s the beauty of Mora’s algorithm: it’s scientifically grounded, but learner-friendly.

👉 Ready to try it out? Start learning with Mora for free.