An ISBN (International Standard Book Number) is the 13-digit identifier that retailers and libraries use to track a specific edition of a book. The rules around when you need one are confusing — here's the practical version.
Do you need an ISBN?
For ebooks: No, technically. Amazon, Apple Books, Kobo, and Google Play don't require one. They assign their own internal identifiers (ASIN on Amazon, etc.). You can publish without one.
For print: Yes, always. Every print-on-demand vendor (IngramSpark, KDP Print) requires an ISBN.
For library distribution: Yes — OverDrive, Hoopla, and Bibliotheca require ISBNs.
For audiobooks: Yes for Audible. Other audiobook retailers vary; we recommend always having one.
Three ways to get an ISBN
1. Use a free Chiify ISBN
Chiify provides a free ISBN with every book upload. We draw from Bowker's pool (the US ISBN agency).
Pros: Free, instant, no admin work.
Cons: Bowker is the recorded publisher of the ISBN, not you. For most authors this doesn't matter. For authors who eventually want to license film/TV rights or sell foreign rights, having the publisher be a third party is sometimes seen as less professional.
2. Buy your own ISBN
You buy a block of 10 from Bowker (in the US) or your country's ISBN agency. About $295 for 10, or $125 for 1.
Pros: You're listed as the publisher. You own the ISBNs forever.
Cons: Cost, and the admin to register them.
3. Skip the ISBN
For ebook-only releases on a single platform (e.g., just Amazon), you don't need an ISBN at all. Amazon assigns an ASIN; the book is fully sellable.
Pros: Free, fast.
Cons: Can't expand to libraries, print, or some retailers later without going back and getting one.
Our recommendation
For your first book: use Chiify's free ISBN. If you later want to upgrade to your own, we'll re-assign the book to your new ISBN — there's no penalty.
For a small press or imprint: buy your own block. It looks more professional and you control the publisher record.
Different formats need different ISBNs
Each format of the same book needs its own ISBN:
- Ebook → one ISBN
- Audiobook → another ISBN
- Paperback → another ISBN
- Hardcover → another ISBN
Chiify auto-assigns the right ISBN to each format if you're using our free pool.
Where the ISBN appears
The ISBN shows up:
- In retailer listings (sometimes hidden under "more details")
- On the EPUB's metadata (so libraries can catalog it)
- On the print book's copyright page and on the back cover near the barcode
You don't need to write the ISBN into your manuscript — we handle that automatically.