ISBN
International Standard Book Number
An ISBN is the 13 digit number that identifies one edition and format of a book, and Google accepts it as the book’s GTIN.
- ISBN-13
What it means
ISBN stands for International Standard Book Number. ISBNs had 10 digits until the end of 2006, but since 1 January 2007 they “always consist of 13 digits”. Every one starts with 978 or 979 and ends in a check digit.1
The International ISBN Agency calls it “essentially a product identifier” for publishers, booksellers, libraries and internet retailers. It identifies the publisher as well as “the specific title, edition and format”. So the paperback and the ebook of one book each need their own.1
Google takes the ISBN in its GTIN field and wants the 13 digit form: “If you have both, include only the 13-digit number.”2
Think of it like this
Record labels do the same with catalogue numbers. The same album on vinyl and on CD gets two, because the shop needs to know exactly which one to order.
For example
A cookery book arrives in a supplier file as 978-0-12-345678-6, hyphenated the way it is printed in the book. In a GTIN field it goes in as 9780123456786. Google accepts the hyphens but ignores them, and ChatGPT’s product feed wants none at all.23
Why it matters
Each format has its own ISBN. So a hardback’s number on the paperback’s row identifies the wrong product, on every channel that matches by GTIN. A supplier file still holding old 10 digit ISBNs needs them converted first, because Google asks for the ISBN-13.2
Not to be confused with
Sources
- International ISBN Agency. What is an ISBN?.
- Google Merchant Center Help. GTIN [gtin].
- OpenAI Developers. Agentic Commerce product feed specification: Products.