Spaced Repetition Schedule Calculator (SM-2 Lite)
Generate next review dates for flashcards using a simplified SM-2 (Anki-style) algorithm.
What this calculates
Spaced repetition uses expanding intervals between reviews — easy cards come back rarely, hard cards often. SM-2, the algorithm behind Anki, adjusts intervals based on a 0-5 quality rating each review. This calculator shows the next 6 review dates for a card given its current ease and interval.
Formula & how it works
If quality ≥ 3: new_interval = previous × ease_factor (or 1 day on first review, 6 days on second). Ease updates: EF = EF + 0.1 − (5−q) × (0.08 + (5−q) × 0.02). Min EF = 1.3. If quality < 3: interval resets to 1 day.
Worked example
New card, quality 4 each review. Intervals: 1d → 6d → 15d → 37d → 91d → 224d.
Frequently asked questions
Quality scale?
0 = blackout, 3 = correct with effort, 5 = perfect recall. Anki simplifies to Again/Hard/Good/Easy buttons.
Why does it work?
Reviewing just before forgetting strengthens memory more efficiently than rote repetition. Backed by 100+ years of cognitive psychology.
Anki vs this?
Anki adds card-level adjustments, leeches, learning steps, and modern FSRS. This calculator is a visualization of the classic SM-2 baseline.