What Is the Difference Between ISBN, ASIN and DOI?

ISBN vs ASIN vs DOI: What's the Difference?

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.

The longer version

	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 to ~$125 depending on 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

ISBN

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?

ASIN

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:

You do not control it. Amazon assigns it, and it belongs to the listing, not to you
It is the fastest way to find your own book. It appears in the product URL and in the product details, and you will paste it into ads, reports and link builders often enough that recording it is worth the thirty seconds

For print books on Amazon, the product carries both an ISBN and an ASIN.

DOI

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.

Which do you actually need to record?

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.

Common exceptions

Audiobooks on Audible/ACX use an ASIN and do not need an ISBN unless distributed elsewhere.
ISBN-10 vs ISBN-13 — ISBN-13 has been the standard since 2007. Older books carry a 10-digit version; converters exist and Amazon often shows both.
Some countries issue ISBNs free (Canada) and some charge substantially (US, UK).
Barcodes are separate. A barcode encodes an ISBN plus price information; it is not an identifier in itself.

Sources

International ISBN Agency, ISBN Users' Manual.
Amazon KDP Help — ASINs and product identifiers.
International DOI Foundation; Crossref registration documentation.

Verified 9 August 2026.

The Author Back Office — the identifier layer.