Amazon KDP is one of the easiest ways to publish your book, but ISBN requirements can be confusing—especially with Amazon offering a free option. In this 2025 guide, we’ll break down exactly when you need your own ISBN, when you can skip it, and why thousands of authors prefer buying their own ISBNs from UPCs.com.

Buy ISBNs for Your Book

⭐ First: Do You Need an ISBN for KDP?

It depends on the format you are publishing:

Paperback: ISBN required (free or your own)
Hardcover: ISBN required
Ebook (Kindle): ISBN not required — Amazon assigns an ASIN
Audiobook: ISBN not required for ACX, but recommended

If you’re publishing a paperback or hardcover, you must use an ISBN—either Amazon’s free ISBN or one you purchase yourself.

Why Many Authors Avoid the Free Amazon ISBN

Amazon’s free ISBN sounds great… until you see what you give up. When you use a free ISBN, Amazon becomes the official “publisher of record.” This affects distribution, professionalism, and your brand.

Here’s what you give up with the free ISBN:

❌ Amazon listed as your publisher (instead of your imprint name)
❌ You cannot use the ISBN on other platforms (IngramSpark, B&N, bookstores)
❌ You cannot sell in most physical bookstores
❌ You cannot transfer the ISBN later
❌ You cannot use the ISBN for updated editions across platforms

For authors building a real publishing brand, the free ISBN is limiting.

Get Your Own ISBN (Keep Full Ownership)

When You Should Definitely Buy Your Own ISBN

Buying your own ISBN is the best choice if any of the following apply:

You want your own imprint/publishing house name on the book.
You want to sell beyond Amazon (IngramSpark, libraries, bookstores).
You want to publish multiple formats (paperback + ebook + audiobook).
You want a long-term author career with consistent metadata.

Owning your ISBN gives you complete control and flexibility—which is why serious authors always purchase their own.

Do You Need a New ISBN for Each Format?

Yes. Every format of your book requires a unique ISBN:

Paperback → 1 ISBN
Hardcover → 1 ISBN
Audiobook → 1 ISBN
Ebook (optional) → 1 ISBN

If you plan to publish more than one version of your book, buying a pack of ISBNs is cheaper and more convenient.

See ISBN Pricing & Bundles

FAQ: Amazon KDP ISBN Rules (2025)

1. Can you use the same ISBN on KDP and IngramSpark?

Yes—as long as you own the ISBN and the files (trim size, interior, cover) are identical.

2. Can you use a free KDP ISBN on other platforms?

No. Free Amazon ISBNs are locked to Amazon only.

3. Do you need an ISBN for Kindle ebooks?

No. Amazon assigns an ASIN automatically. An ISBN is optional but recommended for wide distribution.

4. Should authors buy one ISBN or a block?

If you’re publishing more than one format, a bundle saves money and future headaches.

5. Does an updated edition need a new ISBN?

Yes—major revisions require a new ISBN. Minor updates do not.

What About Barcodes? (Quick Answer)

Your ISBN identifies the book, but you still need a barcode on the back cover for retail scanning. Most authors buy ISBNs and barcodes together for convenience.

Buy ISBN + Barcode Together

Final Recommendation for 2025

If you’re publishing anything beyond a quick Kindle-only ebook, owning your ISBN is the most professional option and gives you full control over your book’s future.

You keep your imprint, control your metadata, and can distribute your book anywhere. That’s why thousands of self-publishers choose UPCs.com for affordable, fast ISBNs.

Get Your ISBN Today

Do You Need an ISBN for Amazon KDP? (Ultimate 2025 Guide)