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SuperMemo World

SuperMemo 20 for Windows

SuperMemo 20 for Windows

Regular price $68.00 USD
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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.

SM-20 ★ current champion
Machine learning — adapts continuously to your memory model
SM-19
Your memory condensed to 40,000 parameters
FSRS
Smart algorithm by Jarrett Ye — a solid modern challenger
SM-15
Spaced repetition classic — battle-tested for two decades
SM-2
The engine behind Anki — the algorithm that started a movement

What's new in SM20

Full changelog →

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.

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.

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.

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

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