What you’ll learn
- Each topic keeps an ease factor
- Successful reviews expand intervals
- Difficult reviews shorten the return
- The schedule adapts per topic
What SM-2 tracks
A typical implementation maintains a repetition count, the current interval, and an ease factor. After a review, the quality score updates those values. Early successful intervals are short; continued success multiplies later intervals by the topic’s ease.
How difficulty maps to the schedule
Spaced Repetition Tracker turns the session labels—Easy, Good, Hard, and Extremely Hard—into scheduling input. The exact goal is not to judge the learner; it is to distinguish fluent recall from effortful or failed recall so the next date reflects reality.
Why use SM-2 for whole topics?
Although SM-2 is widely associated with flashcards, the feedback loop can also schedule a reviewable topic. The quality signal comes from the retrieval activity you choose: practice questions, explanation, demonstration, problems, or cards.
SM-2 is a tool, not a guarantee
No scheduling algorithm knows whether your retrieval task was well designed or whether the rating was honest. Use meaningful recall, correct errors with feedback, and treat the suggested date as a strong default that you can adapt around real deadlines.
Make a review plan for your own topics
Put the method into practice with our free spaced repetition schedule calculator. Enter your exam date and topics to get a daily review plan you can download to your calendar.
Research behind the method
Spacing and retrieval are well-studied learning principles, but no app or schedule guarantees a particular academic result. Use the research as a foundation, then adapt the workload to your material, deadline, and feedback.
Frequently asked questions
Is SM-2 still useful?
Yes. It remains a transparent, lightweight way to adapt intervals from recall quality. Newer algorithms exist, but the learning workflow still depends on consistent, meaningful reviews.
Does SM-2 know my exam date?
Adaptive difficulty and fixed deadlines are different constraints. Use a preset or custom plan when an exam date must shape the final sequence.