Spaced Repetition × SM-2
Based on Wozniak's (1987) SM-2 algorithm, reviews are scheduled right before you forget. Well-known words get longer intervals; forgotten words appear more often.
Spaced Repetition Vocab
Learn English vocabulary with the Ebbinghaus forgetting curve. Free, no sign-up.
What is the Forgetting Curve?
In 1885, psychologist Hermann Ebbinghaus discovered that newly learned information decays exponentially without review. But reviewing at the right moment flattens each forgetting curve, making memories last longer.
No review
With review
※ Simplified illustration based on Ebbinghaus data. Actual forgetting rates vary.
56%
forgotten after 1h
66%
forgotten after 1d
75%
forgotten after 1wk
How does this tool help you memorize?
Three research-backed learning methods combined for maximum retention with minimum effort.
Active Recall: Testing Effect
Roediger & Butler (2011) showed that active recall strengthens memory far more than passive re-reading. The flip-and-rate mechanism applies this principle.
Contextual Learning
Every word comes with a real-context example sentence, collocations, and a bilingual definition — so you understand usage, not just translation.
CEFR-Leveled Progression
Words are organized by CEFR level (A1–B2), from absolute beginner to upper-intermediate, so you can learn at your own pace.
References
- Ebbinghaus, H. (1885). Über das Gedächtnis — Forgetting curve theory
- Wozniak, P. (1987). SM-2 Algorithm — Spaced repetition algorithm
- Leitner, S. (1972). So lernt man lernen — Graded flashcard system
- Roediger, H. & Butler, A. (2011). Testing Effect — Active recall strengthens memory
Quick guide
Use cases, answers, and nearby tools
Compact below-tool notes that help first-run users and repeated visitors move faster without changing the main interface.
How to use
Run a clean first pass
- Select your English level (A1-B2). The system arranges suitable words for you.
- See the English word, try to recall the meaning, then flip to check the answer.
- Rate your recall (forgot / thought about it / instant). The system calculates the optimal next review time.
Examples
Real jobs this page helps with
- 5-Minute Daily ReviewReview due words at scientifically optimal intervals during commute or break time. 2-3x more effective than cramming.
- CEFR-Leveled LearningFrom A1 basics to B2 advanced vocabulary, progressing through the Common European Framework levels.
FAQ
What people usually want to know
What is the forgetting curve?
The forgetting curve, proposed by Ebbinghaus in 1885, shows that memory decays exponentially without review. Timed reviews make memory more durable.
Is spaced repetition effective?
Research confirms spaced repetition extends memory retention 2-3x. This tool uses the SM-2 algorithm to calculate optimal review intervals.
Is my progress saved?
Yes. Progress is automatically saved in your browser's localStorage. No registration or login required.