AI flashcards from a PDF: we made them offline and checked every card
Short answer: yes, in about 5 minutes per chapter on a normal laptop, with no internet. We gave GreenCube two long chapters and asked for flashcards for the exam: each came back with 18 cards and a study guide. Then we checked all 36 cards one by one against the original text. Most were right, but not all, and the mistakes clustered exactly where the chapter jumps between periods. Here are which ones, and the free alternatives.
The test
Two long chapters, the kind that comes up in an exam: Spain's Second Republic (in Spanish, about 4,800 words) and the Industrial Revolution (in English, about 4,700 words). For each we typed what a student would: "make me flashcards of this topic for the exam" (in Spanish), and for the English chapter, the same plus "in Spanish".
We ran it on 19 October 2026 in the real GreenCube app (a test copy of its current version), on a 16 GB laptop with an Intel Core Ultra 5 and its built-in graphics, no graphics card, plugged in and offline. With the small AI, Gemma 4 E2B, the one that runs comfortably on a laptop like this.
The results
| Chapter | Time | Cards | Right | Partly | Wrong | Repeats |
|---|---|---|---|---|---|---|
| Second Republic (Spanish) | 4 min 57 s | 18 | 10 | 2 | 5 | 1 |
| Industrial Revolution (English → Spanish) | 4 min 52 s | 18 | 11 | 4 | 0 | 3 |
The bigger AI does better. We repeated the test with Gemma 4 E4B, the bigger AI GreenCube offers on 16 GB laptops: 30 of 36 cards right, 4 partly, 2 wrong and no repeats.
| Chapter | AI | Right | Partly | Wrong | Repeats |
|---|---|---|---|---|---|
| Second Republic | E2B (small) | 10 | 2 | 5 | 1 |
| Second Republic | E4B (bigger) | 15 | 1 | 2 | 0 |
| Industrial Revolution | E2B (small) | 11 | 4 | 0 | 3 |
| Industrial Revolution | E4B (bigger) | 15 | 3 | 0 | 0 |
We don't publish E4B's time: in this test, an app bug made it rewrite the guide several times before the cards. It's fixed for the next version, and we'll time it again.
"Right" means the card says what the chapter says. "Partly" means it gets the main point but adds or changes a detail. "Wrong" means the chapter says something else. We checked every card by finding the sentence in the original text it came from.
What it got right
Dates and key facts, pulled out cleanly
"When was the Spanish Republic proclaimed?" → "14 April 1931". "What did Samuel Crompton invent in 1779?" → "The spinning mule". "Which left-wing coalition won the 1936 election?" → "The Popular Front". Cards about dates, names and inventions were the most reliable (translated here from the Spanish cards).
An English chapter, flashcards in another language
We gave it the Industrial Revolution chapter in English and asked for the cards in Spanish: all 18 came out in Spanish, and none was wrong. Handy if you study from notes, papers or books in one language and revise in another.
Where it slipped
When the chapter jumps between periods
The Second Republic chapter includes the history of Spain's flag and coat of arms from the 1800s. That's where nearly all the mistakes were: one card says the Second Republic's flag carried the motto "Constitución", when the text is about a flag from the 1820s. Another says the Republic lasted until the Civil War began, when the chapter itself says it lasted until 1 April 1939.
Invented details and the odd repeat
Some cards get the main point but add something the text doesn't say (calling a thread "strong", or saying Arkwright "started the textile industry"), translate a term badly (a cotton gin isn't a "spinning machine"), or repeat an earlier card in other words. And in the tests the written study guide stopped mid-sentence before the cards; the app team found the cause, and it's fixed for the next version.
The practical takeaway: use them, but check them before you study, especially for chapters that mix dates from different periods. Checking 18 cards takes a couple of minutes, which is still far faster than writing them by hand.
Other ways to make AI flashcards for free
All of these run online: you upload your PDF to their site. Facts from their own pages, October 2026; we haven't measured their quality.
| Tool | Free | Uploads your PDF? |
|---|---|---|
| NotebookLM (Google) | Yes: flashcards and quizzes from your documents, exportable as CSV, citing the original text (Google) | Yes, to Google |
| SlideSpeak | Yes, PDFs up to 50 pages, no account, exports to Anki or Quizlet (SlideSpeak) | Yes |
| Flashcards.world | Up to 10 cards without signing up (Flashcards.world) | Yes |
| GreenCube (on your PC) | €9.99 once, no limits; it also chats, summarizes and answers questions about the chapter | No: everything stays on your computer |
If you don't mind uploading your notes to Google, NotebookLM is a very complete free option. If you'd rather they never leave your computer, don't want limits, or study without a good connection, you need an AI on your own PC. We checked what each AI does with your uploads in Which AI doesn't train on your chats?
How to get good flashcards from a PDF
- One chapter at a time. A chapter gives 18 fairly focused cards; a whole book dilutes them.
- Check the cards about dates from other periods. That's where it slips most.
- Delete the repeats and the vague ones ("What is the shaping machine?" → "A machine used in the development of machine tools") and keep the ones that make you think.
- Ask for exam-style questions too and answer them without looking: in our PDF questions test it got 11 of 12 right, in about 15 seconds each.
Will it run on your computer? Check in 30 seconds: with a graphics card it's much faster than on this laptop.
Questions
Can I make AI flashcards from a PDF without internet?
Yes, with an AI that runs on your computer. In our test, GreenCube turned a chapter of about 4,800 words into 18 flashcards and a study guide in about 5 minutes, on a 16 GB laptop with no graphics card and no connection.
Are AI-made flashcards reliable?
Mostly, but not all of them. Of 36 cards we checked by hand, with the small AI 21 were right, 6 partly right, 5 wrong and 4 repeats; with the bigger one, 30 right, 4 partly, 2 wrong and no repeats. The mistakes clustered in the part of the chapter that jumps between periods, so check them before you study with them.
Can it make flashcards in another language than the PDF?
Yes. We asked for Spanish flashcards from an English chapter and all 18 came out in Spanish: 11 right, 4 partly right, none wrong and 3 repeats.
What's the best free app to make AI flashcards from a PDF?
If you don't mind uploading the PDF, NotebookLM makes flashcards for free, exports them as CSV and cites the original text. If you don't want to upload it anywhere or hit limits, you need an AI on your own PC.
Your own AI, on your own PC
GreenCube runs on your computer: no usage limits, no subscription, works without internet. €9.99, paid once.
Get GreenCube