13-digit-ISBN: How will this change impact your links to books on Amazon?

The International Standards Organization (ISO) approved a change to the length of the International Standard Book Number (ISBN) from 10 digits (ISBN-10) to 13 digits (ISBN-13) effective January 1, 2007. Several of you have asked about how the change will impact your links to books on Amazon so we're using this FAQ to answer the most common questions.

1. What's an ISBN? What's an ASIN? What do they have to do with each other and with Associates links?

An ISBN is a unique identifier assigned to every book. The ISBN is frequently printed above the bar code on the back of a book. ASIN stands for Amazon Standard Item Number. Every product in Amazon's catalog has a unique 10-digit ASIN which Associates use when they want to link to that specific item on Amazon.co.uk. Historically, the ASIN assigned to a book was the same as its ISBN. For example, the ISBN for The Innocent Man / John Grisham is 1844137902 and you can find it on Amazon at http://www.amazon.co.uk/dp/1844137902. A recent Associates link to that book might look like this: http://www.amazon.co.uk/dp/1844137902/?tag=assoc-id-20 while an older link might look like this: http://www.amazon.co.uk/exec/obidos/ASIN/1844137902/assoc-id-21.

Amazon plans to continue using 10-digit ASINs so in the future a book's ASIN will be different than its ISBN, just as items in product categories like Electronics or Kitchen may have a manufacturer SKU (stock keeping unit) or other identifier that may be more or fewer characters than the ASIN.

2. Do I have to change any links because of ISBN-13?

No. ASINs for existing books will stay the same so any Associates links to specific books on Amazon will continue to work.

3. If I know the 13-digit ISBN for a book, can I use that in a Product Link to Amazon?

No. Associates Product Links must include the 10-digit ASIN of the item. If you know the 13-digit ISBN, you can look up the ASIN by searching for the book in Associates Central or on Amazon.co.uk. For example, if you wanted to link to the book that has the 13-digit ISBN 9781844137909, you could go to Associates Central -> Build Links -> Product Links and search for "9781844137909". You'll see The Innocent Man in the search results and can click "Get HTML" to generate an Associates link to that item which includes the correct ASIN and your Associates ID.

4. Is there an automated way to create Associates links if I have the 13-digit ISBN?

Yes. Once ISBN-13 is launched, you can programmatically generate Associates links from 13-digit ISBNs using the E-Commerce Service (ECS) from Amazon Web Services. The Web Services team is planning an update that will allow you to look up an item using its 13-digit ISBN. The ECS ItemLookup function already allows lookups using the international article number (EAN) in some countries. They plan to extend that functionality prior to January 1, 2007 to treat 13-digit ISBNs as EANs. Once this capability is available, you will be able to look up a book either using its 10-digit ASIN or its 13-digit ISBN. Watch the E-Commerce Service developer forums and newsletters for further updates about these enhancements.

We recommend using Product Links or ECS when you want to link to a specific item, but you also have the option of using a search results link with the 13-digit ISBN as the keyword. For example, if you wanted to create a link that performs a search on Amazon.co.uk in the Books category for the 13-digit ISBN "9781844137909", you could use a textlink and choose " Link to Search Results ". Select „Books“ as Product Line and enter the 13-digit ISBN as the “Keyword”.

5. I've seen online tools and mapping methods that convert a 13-digit ISBN to a 10-digit ISBN. Can I use one of those to look up the ASIN?

No. Two groups of 13-digit ISBNs have been specified. The initial group starts with 978 and has 10-digit equivalents but the second group that starts with 979 does not. It's quite likely in the short term that the Amazon ASIN for a book with a 13-digit ISBN will be the same as the result if that 13-digit ISBN is converted to a 10-digit ISBN, but in the long term the ASIN that Amazon assigns will have to be a unique identifier because future 979 ISBNs won't have universal 10-digit equivalents. As a result, we recommend looking up ASINs directly on Amazon instead of using an ISBN conversion tool or mapping.