FlashStacksTurn any PDF into flashcards — automatically
Making flashcards by hand is the most tedious part of studying. FlashStacks reads your PDF — lecture slides, textbook chapters, study guides — and AI writes a complete deck for you in seconds.
How it works
1. Upload your PDF
Tap Generate from PDF inside any stack and pick a file from Files, iCloud Drive, or any app. FlashStacks handles lecture slides, scanned textbook chapters, revision guides — anything in PDF format, up to dozens of pages.
2. Choose your focus
Pick High-Yield for a compact deck of just the top examinable facts, or Comprehensive for full coverage of the material. Set a target card count from 10 to 50. There's even a widget-friendly mode that keeps questions short enough to display on your Home Screen.
3. Review and import
AI reads every page — including diagrams, which it flags for optional image occlusion cards — and writes clear question-answer pairs. You see every generated card before it enters your deck, so nothing gets imported that you don't want.
Why AI-generated flashcards actually help you learn
The common objection to auto-generated cards is that writing cards yourself is part of the learning. That's true for some learners — but the research on active recall shows the biggest gains come from testing yourself repeatedly, not from the one-time act of writing the card. Most students who make cards by hand run out of time and only cover a fraction of the material.
AI generation flips the equation: full coverage of your material in seconds, so you spend your study time on the part that actually builds memory — recall practice with spaced repetition.
Built for real study material
- Lecture slides — dense bullet-point slides become clean Q&A pairs
- Textbook chapters — long-form text is distilled into examinable facts
- Diagrams and figures — flagged automatically so you can turn them into tap-to-reveal image occlusion cards
- Any subject — medicine, law, languages, biology, history — if it's in a PDF, it becomes a deck
Then study it from your Home Screen
Here's the part no other flashcard generator has: every card FlashStacks creates is widget-ready. Your generated deck rotates on your Home Screen and Lock Screen throughout the day, so review happens in the gaps of your day — no app-opening required.
PDF to flashcards — FAQ
How many cards can it generate from one PDF?
You choose a target between 10 and 100 cards per generation. For longer documents, the AI prioritises the most examinable content first, and you can generate up to 25 decks a day.
Does it work with scanned PDFs or image-heavy slides?
Yes. Pages with little text are processed with AI vision, so diagram-heavy lecture slides work too. Genuine diagrams get flagged for image occlusion cards.
Is PDF flashcard generation free?
AI deck generation is part of FlashStacks Premium, which comes with a $2.99 first month on the annual plan — enough to convert your current course materials and see if it fits your workflow.
Can I make the cards short enough for a widget?
Yes — pick a card length before generating. "Home Screen" keeps everything under 80 characters, and "Lock Screen" writes terms and short phrases that fit the small Lock Screen widget.
How many decks can I generate per day?
Up to 25 a day, which is far more than anyone gets through in a study session.
Can I edit the generated cards?
Yes — every card can be edited, tagged, or deleted after import, just like cards you write yourself.
Your next exam's deck is one PDF away
Upload your lecture slides and see your deck in under a minute.