SuperMemo World
SuperMemo 20 for Windows
SuperMemo 20 for Windows
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Forget about forgetting
42 years of memory science, now running five algorithms at once
SuperMemo invented spaced repetition software. SuperMemo 20 is its most powerful release yet: five algorithms compete on your personal memory data, and the best-performing one earns more weight in your schedule — automatically, every day. No single formula is trusted blindly. Your memory decides the winner.
Algorithm Arena — the core of SM20
Five spaced repetition algorithms run in parallel on your data. Each makes its own prediction. Each earns weight in proportion to how well it predicts your recall. The result: a schedule that adapts to you faster than ever.
Machine learning — adapts continuously to your memory model
Your memory condensed to 40,000 parameters
Smart algorithm by Jarrett Ye — a solid modern challenger
Spaced repetition classic — battle-tested for two decades
The engine behind Anki — the algorithm that started a movement
What's new in SM20
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PDF import Read and extract directly from PDF files in incremental reading — native format, no conversion needed. |
YouTube in WebView Watch and annotate video inside SuperMemo, with original YouTube references preserved for future review. |
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Math formulas MathJax rendering via WebView — crisp equations in your cards and notes, rendered exactly as intended. |
AI explanations Ask AI to explain while extracting texts — fast answers and elaborations without leaving SuperMemo. |
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64-bit native High-DPI, 4K-ready, hardened Windows 10/11 APIs. Rebuilt for the next 20 years. |
Dark mode Full dark theme with matching dark stylesheet — easier on the eyes during long study sessions. |
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EPub, Email & more Import EPub books, .eml email files, and web pages — with improved duplicate detection that strips tracking parameters automatically. |
Algorithm calibration curves Inspect post-lapse forgetting curves, 4D optimization matrices, and Algorithm Arena heatmaps |
Import anything
Bring your learning material from wherever it lives:
PDF EPub Email (.eml) Wikipedia YouTube Web pages Images
License & requirements
| License | One-time purchase, lifetime license |
| Updates | Free within the SM20 line |
| Platform | Windows 10 / 11 (64-bit recommended; 32-bit version also available) |
| AI & YouTube features | May require a free Google API key |
| Algorithm optimization | SM-20/FSRS optimization may require supermemo.com API access |
| Compatibility | SM16..SM19 collections open in SM20 |
Further reading
What's new in SuperMemo 20 · History of SuperMemo · History of Spaced Repetition
