Knowledge that stays
Build cards. Then remember them.
Learn anything with structured flashcards and smart scheduling powered by the Free Spaced Repetition Scheduler. Create or generate cards and build self-sustained knowledge.
"A thousand years is but an instant. There's nothing new, nothing different; same pattern over and over. The same clouds, same music, the same things I felt an hour or an eternity ago. There's nothing here for me now, nothing at all. Now I remember, this happened to me before. This is why I left. You have begun to find your answers. Although it will seem difficult the rewards will be great. Exercise your human mind as fully as possible knowing that it is only an exercise. Build beautiful artifacts, solve problems, explore the secrets of the physical universe, savor the input from all the senses, filled with joy and sorrow and laughter, empathy, compassion, and tote the emotional memory in your travel bag. I remember where I came from, and how I became human, why I hung around, and now my final departure's scheduled. This way out, escaping velocity. Not just eternity, but infinity." — Waking Life
Free to use · 10 credits to start, 40 more when you sign in · Purchase more anytime
Why it works
Beat the forgetting curve
Memory fades on a predictable curve. A review at the right moment lifts it back up, and every lift lasts longer than the one before. Hashcards picks that moment for you, so you review less and remember more.
Left alone, it fades
The dotted line is what happens without reviews. Most of what you learn today is gone within days.
Each review resets the curve
A review just before you would forget brings recall back to full. That is the moment Hashcards schedules.
The gaps keep growing
Every reset decays slower than the last. Reviews go from days apart to months apart, and the knowledge stays.
What You Can Do
A thoughtfully crafted mobile experience for learning on the go. Master new knowledge and retain it long-term with scientifically-timed reviews.
FSRS Algorithm
Free Spaced Repetition Scheduler
When you review a card, you grade how well you remembered it. Each grade tells the FSRS algorithm exactly how to schedule your next review, optimizing the timing so you review right before you'd forget.
Again
Complete blackout. Card resets to learning phase and you'll see it again in minutes.
Hard
You remembered but struggled. Interval grows slowly, so more practice is needed.
Good
Correct with some effort. Optimal ~2.5x interval growth, which is the sweet spot.
Easy
Instant recall. A big interval jump means you've truly learned this card.
How FSRS Calculates Your Schedule
What is Memory Stability?
Each card has a stability value that represents how long you can remember it. Good grades increase stability exponentially while Again resets it. The higher your stability, the longer until you need to review again.
Why 90% target recall?
FSRS schedules reviews when your recall probability drops to 90%, which is the scientifically optimal point. Review too early and you waste time; too late and you forget. 90% is the sweet spot for long-term retention with minimal effort.
What does the lightbulb mean?
Cards marked with a lightbulb are added to your Daily Review queue, ensuring important cards get extra attention even if they're not technically due yet. Great for exam prep or high-priority material.
Start learning today
Download Hashcards app and unlock new knowledge.
Works offline · Syncs across devices · No account required to start