Publishing glossary
Publishing glossary
What is an ISBN, what does it cost, and do you need one?
An ISBN is a 13-digit book identifier that retailers, libraries, and distributors use to catalog your title. KDP issues one free for paperbacks, or you can buy your own to keep your imprint on record.
Checked:
✓ISBN-13 is the current format✓Free ISBNs exist on KDP✓Ebook and paperback need separate ISBNs
What an ISBN actually is
An ISBN (International Standard Book Number) is the 13-digit number that identifies one edition of one book in one format. Stores, libraries, and wholesalers order, catalog, and return copies by that number, which is how two books sharing a title never get mixed up.
It identifies the edition, not the author and not the words: a paperback and an ebook of the same manuscript carry different ISBNs, and a revised edition needs a new one. The same ISBN is printed twice in a paperback — as text on the copyright page and as the barcode on the back cover.
ISBN vs ASIN vs barcode
These three codes get used interchangeably in publishing forums, and they do different jobs. Amazon assigns an ASIN to every listing automatically, whether or not the book has an ISBN, which is why an ebook can sell on Kindle with no ISBN at all.
| Code | What it identifies | Where it is required |
|---|---|---|
| ISBN-13 | One edition in one format, globally | Print books sold through stores, libraries, and distributors |
| ASIN | One Amazon catalog listing | Every Amazon product page, including ebooks |
| EAN-13 barcode | The scannable image of your ISBN | The back cover of a printed paperback |
Free KDP ISBN vs buying your own
KDP offers a free ISBN for paperbacks, and the publisher of record on that number is Amazon. Buying your own ISBN from your national agency keeps you as the publisher of record, which matters if you want the same number accepted by IngramSpark, bookstores, or your own imprint page.
Fees differ by country and change over time: in the US Bowker sells a single ISBN for around $125 and a block of ten for around $295, while agencies in Canada and the UK issue them free to publishers. Confirm the current fee with your national agency before you buy a block.
Amazon ebooks do not need an ISBN at all. Buy one only if you plan to sell the ebook outside Amazon, such as through Apple Books or Kobo.
- Ebook ISBNs are not required on Amazon
- Each format needs its own ISBN
- An imprint name appears as publisher
Where the ISBN appears
The ISBN appears on the copyright page and as the EAN-13 barcode on the back cover. Keeping it consistent between your files and KDP metadata prevents listing errors.
FAQ
Frequently asked questions
Do I need to buy an ISBN for KDP?
Not necessarily. KDP provides a free ISBN for paperbacks. If you want your own publisher of record or plan to distribute outside Amazon, buy one from your country's ISBN agency.
How much does an ISBN cost?
It depends on your country. In the US, Bowker charges around $125 for a single ISBN and around $295 for ten; agencies in Canada and the UK issue them free. Blocks are cheaper per number than singles, which is why series authors buy ten.
Can I reuse one ISBN for ebook and paperback?
No. Every format and edition needs its own ISBN. Reusing one causes cataloging conflicts.
Does an Amazon ebook need an ISBN?
No. Amazon identifies ebooks by ASIN and accepts them without an ISBN. You only need an ebook ISBN to sell that ebook in stores outside Amazon.
Is the ASIN the same as the ISBN?
No. An ASIN is Amazon's own catalog code for a listing, and an ISBN is the publishing industry number for an edition. A paperback on Amazon has both.
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