KDP offers a free ISBN for your paperback and hardcover. The catch: when you use a free KDP ISBN, the "publisher" on record is Amazon/KDP, and the ISBN can only be used on Amazon — it cannot be transferred to IngramSpark or another distributor. If you plan to distribute exclusively through Amazon, the free ISBN is perfectly adequate. If you want to go wide — selling through IngramSpark, bookstores, or libraries — you need to purchase your own ISBN and bring it to KDP, which then allows you to use that same ISBN on other platforms.
No. Amazon does not require an ISBN for Kindle eBooks. Your eBook is identified by its ASIN on Amazon and by an internal identifier on other platforms. If you publish your eBook on other platforms (Apple Books, Kobo, Google Play), those platforms may assign their own identifiers, or you can provide an ISBN — but it's optional on most platforms and not required for the vast majority of indie authors.
How much does an ISBN cost?
In the US, individual ISBNs from Bowker cost around $125 each. A block of 10 costs around $295 and a block of 100 around $575 — making bulk purchases significantly cheaper per unit. In the UK, Nielsen offers ISBNs through the Nielsen Title Editor. The free KDP ISBN is genuinely free for Amazon-only distribution.
Can I use the same ISBN for eBook and paperback?
No. Every distinct format requires its own ISBN. A paperback and a Kindle eBook of the same title are different products and must have different ISBNs. Using the same ISBN for multiple formats violates ISBN standards and can cause catalogue errors with retailers and libraries.
If I change my book cover, do I need a new ISBN?
No — cover changes don't require a new ISBN. An ISBN identifies the intellectual content of a specific edition, not its cover design. You need a new ISBN when you make significant changes to the text content (a new edition), change the format (paperback to hardcover), or change the publisher of record.
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