How to Turn Ebook Highlights into Flashcards on Android (3 Ways)

Manual route: export highlights from your reader as a text or CSV file, reshape it into 'front;back' lines, import into AnkiDroid. Works with any reader; takes ten minutes per book and breaks whenever you re-highlight.

Paid route: Readwise or a similar service pulls Kindle and app highlights into the cloud, then pushes them to Anki or shows them in its own review. Reliable, but a subscription, and Kindle-only for DRM books.

No-export route: use a reader that treats every highlight as a card. GemReader is a free Android EPUB and PDF reader with a built-in spaced-repetition Review page; highlights become cards the moment you make them, and your existing Anki decks (.apkg / .txt) import alongside them.

Kindle-store books with DRM cannot be opened by any third-party reader, so for those the paid route or Amazon's own export is the only option.

If your books are EPUB or PDF and you are on Android, skip the export step entirely — a reader with review built in removes the friction that makes most people stop after week one. If your library is locked Kindle purchases, the highlight-sync services are the only path that doesn't involve retyping.

The research on this is unambiguous: highlighting has close to zero effect on retention on its own, while retrieval practice — being asked the question and producing the answer — is one of the strongest study techniques measured. A highlight is a bookmark for a future question you never get asked.

Spaced repetition closes that gap by re-asking at growing intervals. The problem has never been the method; it is the pipeline from 'I marked this sentence' to 'this sentence is a card I'll see next Tuesday'. Every step in that pipeline is a place people quit.

Most Android readers can export highlights. Moon+ Reader writes a text file per book; ReadEra Premium and Librera export notes as text or HTML; Kindle for Android emails a notebook export for non-DRM sideloaded books.

Open that file on a desktop, reshape each highlight into a line with a separator between question and answer — for a textbook definition that usually means splitting the sentence at 'is' or 'means' — save as a tab- or semicolon-separated text file, and import it into AnkiDroid or desktop Anki with the matching field mapping.

It works for any reader and any format the reader opens. It also means the deck is a snapshot: new highlights need another export, edits made in the reader never reach the deck, and cleaning the export is dull enough that most people do it once.

Readwise is the best-known: connect your Kindle account or upload exports from other apps, and it collects highlights centrally, resurfaces a few each day by email, and can push them into Anki through its own integration. Competitors do a similar job with different pricing.

It is the right answer for Kindle purchases, which no third-party Android reader can open because of DRM. The trade-offs are a monthly fee for something that is fundamentally a text file mover, your reading data sitting on a third-party server, and — unless you set up the Anki sync — a review model that shows you highlights rather than testing you on them.

The shortest pipeline is no pipeline. In GemReader, a highlight is already a card: select a passage, pick one of six colours, optionally type a note, and it appears on the Review page with the spaced-repetition scheduler attached. The front is the highlight, the note becomes the back, and the book title and location come along so the card never loses context.

Highlights and notes can be tagged, and the Review page can drill by book, by tag or across the whole library. If you already have Anki decks, import the .apkg or .txt file and they sit in the same queue as your own highlights — one review session covers both.

Nothing leaves the phone. There is no account, no server and no export step; the library and the deck are the same encrypted database. That also means it only helps with books the app can open: EPUB, PDF, MOBI and DRM-free AZW3. Not sure whether a file is locked? The free Book Checker tells you in the browser without uploading it.

PDFs highlight the same way as EPUBs in GemReader as long as the file has a text layer. A scanned handout is a stack of images; there is no text to select, so there is nothing to highlight or to put on a card. Run it through OCR first — most phone scanning apps and desktop PDF tools can — and re-import. The PDF Text Layer Checker tells you which kind of PDF you have.

Whatever the pipeline, the cards decide whether it works. Highlight the claim, not the paragraph; a card that takes thirty seconds to read gets skipped. Put the question in the note: 'why does X fail under Y?' on the back of the highlight that explains it turns a passive re-read into a retrieval prompt.

Use colours as categories you'll later filter by — definitions, examples, things you disagree with — rather than as an intensity scale. And expect to delete: a deck full of cards you always get right is a deck you stop opening.

GemReader is free, has no ads and needs no account. Textbooks, lecture PDFs and workbooks live in one library; highlight as you read, then study those highlights as flashcards without exporting anything or leaving the app. Download for Android, import an EPUB, and the first highlight you make is the first card in the deck.