Forgetting Curve
Hermann Ebbinghaus discovered: without review, 50% of information is lost within an hour, 70% within a day, 80% within a week. This is biology, not laziness.
Science
Spaced Repetition FSRS – The Scientific Way to Remember English Words
Ebbinghaus's forgetting curve shows that 80% of information is lost within a week without review. Spaced repetition reverses this curve: each well-timed review doubles how long a word stays in your memory.
Spacing Effect
Reviewing at increasing intervals is far more effective than cramming. Five minutes across five days beats twenty-five minutes in one sitting.
Active Recall
Trying to remember a word before seeing the answer is the key to retention. Passive re-reading is nearly useless. FSRS is built entirely on active recall.
Desirable Difficulty
Optimal review happens when a word is on the edge of forgetting. Too early – wasted time. Too late – forgotten. FSRS calculates this exact moment.
What Is FSRS and Why It Outperforms SM-2
SM-2 is a 1987 algorithm still used in Anki. It works, but doesn't account for individual learning patterns. FSRS (Free Spaced Repetition Scheduler) is a 2022 algorithm based on machine learning.
FSRS analyzes your review history and adapts intervals personally: if you easily remember abstract words but struggle with phrasal verbs – FSRS shortens intervals for phrasal verbs. This is personalization at the individual word level.
How It Works in Practice
You save a word while reading. Tomorrow it appears in your daily plan. Remembered it? FSRS extends the interval to 3 days. Remembered again? 7 days. Then 14, 30, 60 days. After 5-7 successful reviews, the interval can grow to 6-12 months.
Forgot a word? FSRS resets the interval and starts fresh, but accounts for the fact that the word was once in your memory – relearning happens faster.
Results Over Time
- 1 month: 150-200 words locked into long-term memory
- 3 months: 500-700 words, 80%+ retained for 30+ days
- 6 months: 1000-1500 words with regular daily practice
- 1 year: 2000-3000 words, confident B1-B2 level
5 Minutes of Review = 500 Words in 3 Months
Spaced repetition isn't "cramming." It's 5 minutes a day during which FSRS cycles through 20-40 words at optimal pace. Over 3 months, this builds a vocabulary that lasts years.
FSRS > SM-2
2022 algorithm – schedules reviews more precisely than classic SM-2 in Anki.
Automatic
No planning needed – FSRS decides the perfect review moment.
5 Min/Day
Daily review session: 20-40 words in just 5 minutes.
FAQ
Spaced Repetition Questions
The science of memory that works.
Words are reviewed at increasing intervals: 1–3–7–14–30 days. Each interval is calculated individually by FSRS.
FSRS uses machine learning for personalized intervals. SM-2 (Anki) is a 1987 algorithm without adaptation.
3-7 minutes for up to 500 words. 10-15 minutes for 1000+. The system regulates flow automatically.
After 5-7 successful reviews, retention exceeds 90%. Intervals grow to 6-12 months.
Start Remembering Words Forever
FSRS algorithm + contextual reading = permanent vocabulary growth.