ISBNs Explained for Self-Publishers

An ISBN (International Standard Book Number) is the unique number that identifies one edition of a book. Bookstores, libraries, and distributors use it to find and order your book. Here's what independent graphic novelists need to know.

One ISBN per edition

Each format needs its own ISBN: the paperback, the hardcover, and (if you use one) the ebook are separate editions. A new edition with significant changes — a new trim size, new content — usually needs a new ISBN too. Fixing a typo doesn't.

The free KDP ISBN

KDP offers a free ISBN for paperbacks and hardcovers. It's the simplest option, and it's fine if you're selling mainly on Amazon. The catch: the book is listed with KDP's imprint information rather than yours, and that ISBN can only be used for that edition through KDP.

Buying your own

If you buy your own ISBN, you are listed as the publisher, under your own imprint name. That matters if you want to:

• Publish the same edition through both KDP and another distributor such as IngramSpark.
• Look like an established publisher to bookstores and libraries.
• Keep full control of the edition's details.

Who sells ISBNs depends on your country — in the US, it's Bowker; many other countries have their own national agency, and some issue them free. ISBNs are usually cheaper bought in blocks, which helps if you're publishing a series in several formats.

Barcodes

The barcode on a back cover encodes the ISBN (and sometimes the price). KDP adds a barcode automatically when you use its cover tools. If you design your own cover, leave space in the area KDP specifies.

ASIN vs. ISBN

On Amazon, every product also has an ASIN — Amazon's own number. For print books the ISBN and ASIN are related but different; for Kindle ebooks, Amazon uses an ASIN and you don't need an ISBN at all.

A practical choice

• Selling mainly on Amazon, starting out: the free KDP ISBN is fine.
• Planning wide distribution, a publishing imprint, or a big series: buy your own, ideally in a block.

See distribution beyond Amazon for how this fits into reaching bookstores and libraries.