Glossary
ISBN vs ASIN
ISBN vs ASIN: An ISBN is the international 13-digit book identifier issued by national agencies, needed for print distribution to bookshops and libraries. An ASIN is Amazon’s own 10-character product code, assigned free to every listing. A Kindle ebook needs only an ASIN; a paperback needs an ISBN, which KDP can provide free.
When you need an ISBN
- Paperbacks and hardcovers, on every platform.
- Ebooks distributed to libraries or through aggregators that require one.
- When you want the publisher of record to be your own imprint rather than Amazon or the aggregator.
Free versus purchased ISBN
KDP, IngramSpark and Draft2Digital offer free ISBNs, but the publisher of record becomes them, and a free ISBN cannot be reused on another platform. Buying your own (Bowker in the US, free from the national agency in France, Canada and others) makes you the publisher and lets one edition carry one number everywhere.
ASIN in practice
Every Amazon edition gets its own ASIN: Kindle, paperback and hardcover are three ASINs linked on one page. The ASIN is what you use in Amazon Ads, in affiliate links and in the book’s URL, and it is assigned the moment the listing is created.
Frequently asked questions
Does an ebook on KDP need an ISBN?
No. Amazon assigns an ASIN. You may add an ISBN you own, but it is not required.
Can I use the same ISBN for the ebook and the paperback?
No. Each format and each edition needs its own ISBN.
Where do I get an ISBN in France or the UK?
From AFNIL in France (free for small publishers) and from Nielsen in the UK (paid).