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ISBNs without the traps

By R. S. Breed · Updated

An ISBN is a 13-digit number that identifies one specific edition of one specific book. It's how bookshops, libraries and distributors tell your paperback apart from your hardcover, and your book apart from the other few million on sale.

ISBNs cause more first-timer worry than almost anything else in self-publishing, mostly because a couple of the choices are hard to undo. The good news is there are only a handful of rules. Once you know them, you can make the decision in ten minutes.

Do you need one?

It depends on the format and where you're selling.

Format Need an ISBN?
Kindle ebook on KDP No. Amazon gives it an ASIN instead.
Ebook on other stores Depends on the store or distributor. Some distributors can assign one for you, but that number generally only works through them.
Paperback Yes.
Hardcover Yes, a separate one.
Audiobook Depends on the platform.

If you only ever plan to sell a Kindle ebook, you can skip this guide for now. The moment you add print, you need to decide.

The core rules

  1. One ISBN per format. Your paperback, hardcover and ebook each get their own number. You can't reuse one across formats.
  2. A new ISBN for a substantially revised edition. Fixing typos doesn't need a new number. Adding new chapters or rewriting large parts does.
  3. The ISBN records who the publisher is. Whoever the ISBN is registered to is the "publisher of record". That's the part that matters most, and it's where the traps are.
  4. Treat an ISBN as tied to whoever registered it. Individual ISBNs can't be resold or transferred, and if a book changes publisher, the new publisher has to assign one of its own. Don't count on moving a number to your name later.

Free ISBNs: convenient, with strings

Both KDP and IngramSpark offer free ISBNs. They're genuinely free and they work. The catch is where they work.

KDP's free ISBN

  • It can only be used on KDP. You can't take it to another printer or distributor.
  • Your imprint shows as "Independently published" on the product page.

IngramSpark's free ISBN

  • Only available to US self-publishers.
  • It can only be used for your title on IngramSpark.
  • Your imprint shows as Ingram's imprint, Indy Pub, not yours.
  • Any title using it must go into Ingram's wholesale distribution.

When free is fine

A free ISBN is a reasonable choice if:

  • You're testing the waters with a first book and only selling print on Amazon.
  • You don't care what the imprint line says.
  • You accept that if you later want the same paperback in bookstores through another distributor, you'll need a new ISBN and it will be treated as a separate edition.

When to buy your own

Buy your own if:

  • You want to publish the same print edition through both KDP and IngramSpark (a very common setup).
  • You want your own imprint name on the book.
  • You plan to write a series and want everything consistent from the start.

The cost of buying later is mostly hassle: a new ISBN means a new edition, and reviews and sales history may not carry over the way you'd like.

The reseller trap

Some websites sell single ISBNs cheaply. Many of them are resellers. The problem is that a reseller ISBN is often registered to the reseller, which makes the reseller the publisher of record, not you.

That can mean:

  • The reseller's name appears as publisher in trade databases.
  • KDP may reject your book because the imprint you type doesn't match the ISBN registration.
  • You have no control over the metadata attached to that number.

The fix is simple: buy ISBNs from the official agency for your country (listed below), or get a free one from a platform with your eyes open. Avoid third parties offering "cheap ISBNs", and be especially wary of publishing packages that include "an ISBN" without saying whose name it's registered in.

Imprint name matching

If you use your own ISBN on KDP, the imprint name you type must match your ISBN registration exactly. KDP's help pages are blunt about this: it's case-sensitive, and even extra spaces at the end cause a mismatch.

A few habits that prevent problems:

  • Pick your imprint name before you buy. Something simple, with no punctuation you'll mistype.
  • Copy and paste it from your ISBN account rather than typing it.
  • Use exactly the same form everywhere: KDP, IngramSpark, your copyright page.

You don't need to register a company to have an imprint name. In most places it's just the publisher name you enter when you register the ISBN. If you plan to trade under that name more broadly, check your local business name rules.

Where to get ISBNs, by country

Generally, you buy from the ISBN agency in the country where you live and publish from.

Country Agency Cost
United States Bowker (myidentifiers.com) US$125 for one, US$295 for 10, US$575 for 100
United Kingdom Nielsen (Nielsen ISBN Store) £93 for one, £174 for 10 (including VAT)
Australia Thorpe-Bowker (myidentifiers.com.au) A$44 for one, A$88 for 10, plus a one-off A$55 new publisher fee
Canada Library and Archives Canada Free for eligible Canadian publishers and self-publishers
New Zealand National Library of New Zealand Free for publishers located in New Zealand

A few notes:

  • US and Australian prices above come from secondary sources (checked September 2026), because we couldn't load the agencies' own price pages. UK prices are from Nielsen's store. Check the agency's site on the day you buy.
  • Australia: Thorpe-Bowker is the official agency for publishers located in Australia. The A$55 fee is added the first time you buy.
  • Canada: Self-publishing authors must be physically located in Canada. Canadian publishers publishing only in French apply through BAnQ instead.
  • Blocks save money. In the US a block of ten costs less than three singles, and in the UK less than two. In Australia, on the secondary-source prices above, ten cost the same as two singles. If you'll publish more than one book or format, a block usually pays for itself.

A simple decision path

  1. Kindle ebook only? No ISBN needed. Stop here.
  2. Adding a paperback, only on Amazon, and happy with "Independently published"? The free KDP ISBN is fine.
  3. Want bookstores and libraries, or your own imprint? Buy your own from your country's agency (or get them free if you're in Canada or New Zealand).
  4. Planning a paperback and a hardcover? You need two ISBNs. Buy a block.
  5. Anyone offering a cheap single ISBN from a site that isn't your national agency? Check whose name it's registered to before you pay.

What to record once you have them

Keep a simple list: ISBN, title, format, trim size, date assigned, and where it's used. When you have several books in several formats, you'll be glad of it. Assign each number in your agency account with the correct title and format as soon as you use it, so the trade databases show your book properly.

Sources

Platforms change their rules often. If something here is out of date, tell us in the forum and we'll fix it.

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