FAQ: ISBN-13 for Amazon Associates

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. This list of Frequently Asked Questions provides information about how the new ISBNs affect Amazon Associates.

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.com. Historically, the ASIN assigned to a book was the same as its ISBN. For example, the ISBN for The Great Gatsby is 0743273567 and you can find it on Amazon at http://www.amazon.com/dp/0743273567. A recent Associates link to that book might look like this: http://www.amazon.com/dp/0743273567/?tag=assoc-id-20 while an older link might look like this: http://www.amazon.com/exec/obidos/ASIN/0743273567/assoc-id-20 .

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.

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.

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.com. For example, if you wanted to link to the book that has the 13-digit ISBN 9780743273565, you could go to Associates Central -> Build Links -> Product Links and search for "9780743273565". You'll see The Great Gatsby 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.

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

Yes. You can programmatically generate Associates links from 13-digit ISBNs using the Product Advertising API. The ItemLookup function allows you to look up items using an ASIN, international article number (EAN), or other identifiers. The IdType “EAN” can be used to lookup products by 13-digit ISBNs. For example, if you wanted to look up the book with the 13-digit ISBN 9780743273565 you would use the following API parameters:

Operation=ItemLookup
ItemId=9780743273565
IdType=EAN
SearchIndex=All

For more information, see the Product Advertsing API Documentation.

We recommend using Product Links or Product Advertsing API 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.com in the Books category for the 13-digit ISBN 9780743273565, you could use a link like the following (replacing assoc-id-20 with your Associates ID): http://www.amazon.com/gp/search?keywords=9780743273565&index=books&linkCode=qs&tag=assoc-id-20

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. Note that the final digit of an ISBN is a calculated value (a "checksum") so even though most digits of a 13-digit ISBN that begins with 978 are the same as its 10-digit equivalent, the last digit will usually be different.

It's quite likely in the short term that the 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.