What Is an ASIN and How Is It Different from an ISBN?
TL;DR:An ASIN is Amazon’s internal product identifier used to track items in their store. An ISBN is the global standard identifier for books. Kindle ebooks receive an ASIN automatically and do not require an ISBN, but print books need an ISBN for distribution beyond Amazon.
If you have published or shopped for books on Amazon, you have probably seen both ASINs and ISBNs associated with a single title and wondered what the difference is. They serve similar purposes — identifying a specific product — but they operate in entirely different ecosystems.
An ASIN, or Amazon Standard Identification Number, is a 10-character alphanumeric code that Amazon assigns to every product in its catalog. Every Kindle ebook automatically receives an ASIN when you publish through KDP, and every physical product sold on Amazon (books included) has one. ASINs exist only within Amazon’s system. No bookstore, library, or distributor outside of Amazon uses them.
An ISBN, or International Standard Book Number, is a globally recognized 13-digit identifier managed by the International ISBN Agency. In the United States, Bowker is the sole authorized agency for issuing ISBNs. Unlike ASINs, ISBNs are used by every part of the book supply chain — retailers, wholesalers, libraries, and distributors worldwide.
For Kindle ebooks, you do not need an ISBN. Amazon assigns an ASIN, and that is sufficient for listing and selling the ebook on the Kindle Store. If you choose to add an ISBN to your ebook (because you are also distributing through other retailers), you can enter it during the KDP setup process, but it is not required.
For print books on KDP, the situation is different. Every print book needs an ISBN, but KDP will provide one for free if you do not supply your own. If you want to distribute your print book beyond Amazon — through IngramSpark, Barnes & Noble, or independent bookstores — you will need to purchase your own ISBN from Bowker.
One detail that confuses many authors: a print book listed on Amazon will have both an ASIN and an ISBN. For print editions, Amazon typically uses the ISBN as the ASIN (the 10-digit ASIN corresponds to the ISBN). For Kindle editions, the ASIN is a separate identifier unrelated to the ISBN system.
The key takeaway is that ASINs are Amazon’s internal system, and ISBNs are the universal standard. If you only sell through Amazon, ASINs handle everything. If you want your book discoverable and orderable across the global book trade, you need ISBNs.
- Amazon Seller Central: “What is an ASIN?”
- Bowker / MyIdentifiers.com
- International ISBN Agency