They belong to three different systems. An ISBN is the international book trade standard, issued by a national agency, and identifies one edition of one book in one format. An ASIN is Amazon's own internal product code, assigned automatically to everything Amazon sells. A DOI identifies scholarly and digital objects — journal articles, datasets, chapters — and is almost never needed by an indie author.
| ISBN | ASIN | DOI | |
|---|---|---|---|
| Stands for | International Standard Book Number | Amazon Standard Identification Number | Digital Object Identifier |
| Issued by | National ISBN agency (Bowker, Nielsen, etc.) | Amazon, automatically | A registration agency such as Crossref or DataCite |
| Scope | The global book trade | Amazon only | Scholarly and digital objects |
| Cost | Free in some countries, paid in others — by country | Free | Paid, usually via an institution or publisher |
| Owned by | You, if you buy it | Amazon | The registrant |
| Portable | Yes | No | Yes |
| Format-specific | Yes — one per format | Yes — one per Amazon product | Version-specific |
These two get confused because on Amazon they sit side by side in the same product details box. They answer different questions.
No. An ISBN identifies a book edition everywhere books are sold; an ASIN identifies a product listing on Amazon only. The ISBN is yours if you bought it, and follows the book to every retailer, library and wholesaler. The ASIN is Amazon's, and means nothing anywhere else.
What makes them look alike is how Amazon labels print books. A print listing keys off the book's ISBN, so the identifier in the ASIN position is usually a number derived from that ISBN. Kindle ebooks get a code Amazon generates, typically beginning "B0", whether or not you supply an ISBN.
It depends on the format and where you sell it:
| You are publishing | Identifier you need | Why |
|---|---|---|
| Kindle ebook, sold only on Amazon | ASIN only | Amazon assigns it; Kindle ebooks do not need an ISBN |
| Ebook sold wide | Optional at most stores | Apple, Google Play and Kobo's own store accept ebooks without one; Kobo's partner retailers do not. Draft2Digital assigns one free |
| Paperback or hardcover on KDP | ISBN — free from KDP, or your own | Print always needs one; the ASIN comes on top |
| Print through IngramSpark as well | Your own ISBN | IngramSpark's free ISBN cannot be used on another platform |
You never apply for an ASIN. It appears when the listing goes live.
KDP's free ISBN is offered for paperback and hardcover only, registered to “Independently published”. It also cannot be used with another publisher or printer, so a paperback that later goes to IngramSpark needs a different ISBN there — and becomes, in the book trade's records, two separate products. An ISBN you own avoids both problems. The full trade-off is in KDP ISBN vs your own ISBN.
The ASIN belongs to the listing, so it stays put while the listing does. What changes it is anything that makes a new product: a new edition published as a new title, a new ISBN on a print book, or unpublishing and republishing rather than updating in place. Sales rank and the listing's history stay with it too, which is the practical reason to update a book rather than republish it.
The one that matters for nearly every author. It is how bookstores, libraries, distributors and wholesalers order a specific edition. One per format: the paperback, hardcover, ebook and audiobook are four products.
Whether you need one at all depends on where you sell. Print requires it; Kindle ebooks do not. See Do I need an ISBN to self-publish?
Amazon assigns an ASIN to every product it lists, books included. For a Kindle ebook the ASIN often is the only identifier, which is why Amazon-only ebook authors can skip ISBNs entirely.
Two things worth knowing:
For print books on Amazon, the product carries both an ISBN and an ASIN.
Persistent identifiers for scholarly outputs — journal articles, conference papers, datasets, and increasingly book chapters in academic publishing. They resolve to a permanent URL through the DOI system, so a citation still works when the hosting site changes.
Most indie authors will never need one. The exceptions are narrow: academic monographs, edited collections where individual chapters need citing, and non-fiction aimed at a research audience where citability matters. Getting a DOI generally means going through a registration agency, which usually means an institution or an academic publisher.
If you are writing commercial fiction or general non-fiction, this is a box you can leave unticked.
For a working author: ISBN per format, ASIN per Amazon listing. Both, per title, kept somewhere you can retrieve in seconds — because you will look them up for the rest of your career.
Verified 9 August 2026.