How to get an ISBN (and when the free one is enough)

Somewhere between finishing your manuscript and holding your book, a thirteen-digit number shows up on the to-do list — and with it, a surprising amount of confusion. Do you need one? Do you need three? Is the free one a trap? Should you really pay $125 for a number? We register ISBNs every week as part of publishing our authors’ books, so here is the whole thing explained plainly: what an ISBN actually is, the two real ways to get one, exactly what each costs in 2026, and the honest framework for choosing — including the cases where the free number is genuinely fine.

First, what an ISBN is — and what it isn’t

An ISBN (International Standard Book Number) is a 13-digit identifier that tells bookstores, libraries, distributors, and retailers exactly which book — and which version of that book — they’re looking at. Think of it as a SKU for the book world: the paperback of your novel is one product, the hardcover is another, and each needs its own number so a store in Boise and a library in Baton Rouge can order the same edition without ambiguity.

Two things an ISBN is not. It is not copyright — your words are protected automatically the moment you write them, and formal registration is a separate $45–$65 filing with the U.S. Copyright Office (we’ve explained that in how to copyright a book). And it is not a sales requirement everywhere — as you’ll see in a moment, some books are sold every day without one.

Step 1 — Decide whether you actually need one

Here’s the part most guides bury: not every book needs a purchased ISBN.

• Kindle ebook only? Amazon does not require an ISBN for Kindle ebooks. It assigns its own identifier, an ASIN, when you publish. Millions of ebooks sell with no ISBN at all.
• Print book? Yes — every printed edition needs an ISBN. The only question is whose: one you bought, or a free one supplied by the platform.
• Wide distribution ambitions? If you want the same edition listed across Amazon, Barnes & Noble, bookstores, and libraries under your imprint, you need your own purchased ISBN — the free platform numbers can’t travel.

Step 2 — Know the only official source (and the prices)

In the United States, ISBNs come from exactly one official agency: Bowker, through its site myidentifiers.com. The Library of Congress itself directs authors there. Anyone else selling you an ISBN is reselling — and resold ISBNs list the reseller as the publisher of record, which defeats most of the point of buying one. Bowker’s current pricing:

Two facts make the math friendlier than it first looks. ISBNs never expire — a ten-pack bought today assigns your next decade of books. And you’ll use more than you think: paperback + hardcover + an ebook edition you assign an ISBN to is three numbers for one book. Buy the single at $125 and then write a second book, and you’ll wish you’d spent the extra $170 once.

Step 3a — Buying your own from Bowker, step by step

1. Go to myidentifiers.com and create an account. The name you register as publisher here is the name that will appear as publisher of record — your own name, or an imprint name you’ve chosen.
2. Choose your package — 1, 10, or 100 — and check out. The numbers appear in your dashboard immediately.
3. Assign a number to each format. In your dashboard, attach title, subtitle, author, format, and publication date to one ISBN per edition. Do this carefully — this metadata is what feeds retailer and library systems.
4. Enter the ISBN when you publish. KDP, IngramSpark, and every other platform ask for it during setup, and it gets printed into your copyright page and back cover.

Step 3b — Or take the free one (with eyes open)

Amazon KDP will give you a free ISBN for paperbacks and hardcovers during setup — a real, valid number that costs nothing. Here is the fine print, straight from KDP’s own terms:

• It only works on Amazon. A free KDP ISBN cannot be used to publish that edition through IngramSpark, Barnes & Noble, or anywhere else. Going wide later means getting a new ISBN — and a wide edition that’s a separate product from your Amazon one, with separate reviews.
• The publisher of record reads “Independently published.” Not your name, not your imprint. Readers rarely check; bookstores and reviewers sometimes do.

So the honest decision framework is short. Take the free ISBN if you’re publishing one book, on Amazon only, and the publisher line doesn’t matter to you — a family memoir printed for relatives is the classic case. Buy your own if any of these is true: you want your book in stores or libraries beyond Amazon, you want your own imprint name on the record, or you plan more than one book or format — because at $29.50 apiece in the ten-pack, owning your numbers is one of the cheaper pieces of the whole publishing project. For where that fits among all the other line items, our complete cost breakdown puts the ISBN next to editing, covers, and printing. We’ve also published a companion piece just on the pricing question — how much does an ISBN cost — if that’s the only number you came for.

Outside the U.S.: a 60-second detour

ISBNs are issued country by country. Canadian authors get theirs free from Library and Archives Canada. In the UK and Ireland, the Nielsen ISBN agency sells them, much as Bowker does in the States. If you live abroad but publish through U.S. platforms, you use your own country’s agency — the numbers work worldwide either way.

ISBN, ASIN, LCCN, copyright — the untangling table

If you publish with us, this whole page is our job

One honest note about our own service, since readers ask. When USA Publishing House publishes a book, ISBN registration is included in every package — assignment, metadata, and barcode handled, with the book distributed to Amazon, Barnes & Noble, and 20+ platforms, and 100% of rights and royalties staying with the author. It’s one of the dozen small jobs that make up done-for-you publishing, priced flat and in the open. Authors reach us from every state — this week that includes readers of our Louisiana and Texas publishing pages — and the process is identical everywhere: remote, transparent, and approved by you at every step.

Questions authors ask us about ISBNs

Sources & further reading: ISBN pricing is Bowker’s published myidentifiers.com pricing ($125 / $295 / $575), current as of September 2026; Bowker’s status as the only official U.S. ISBN agency is confirmed by the Library of Congress and ISBN.org. Free-ISBN restrictions (Amazon-only use; “Independently published” imprint) are from Amazon’s published KDP help documentation. Copyright fees are from the U.S. Copyright Office fee schedule.