How to Self-Publish a Book With a Co-Author

One KDP account publishes the book and gets paid, so if you write with a co-author, the two of you need to agree in writing how the royalties are shared. KDP lets you list both names on the book, but the help pages I read do not describe splitting the money between people. That part is up to you. If you want to know what a sale earns before you split it, see what reasonable Amazon royalties are.

Here is what KDP, Draft2Digital and the US Copyright Office say, and what I would do before the book goes live.

Can I list two authors on a KDP book?

Yes. KDP’s help page on Authors & Contributors says your book needs at least one author or primary contributor, and that “If you have more than one author, you can list them in the Contributors section.” You choose “Author” from the contributor type list. You can include up to 10 contributors when you set up a paperback or an ebook. If more than two writers share one book, see how to self-publish an anthology.

The name in the Author section shows first on the book’s detail page, and the other names follow in the order you entered them. KDP also says you will not be able to change the primary author field after the book is published, so agree who goes first before you hit publish.

Who does KDP pay?

The account holder. KDP’s Terms and Conditions say the Amazon party that made the sale “will pay you the applicable royalty” and that you need to register a valid bank account in your KDP account to receive royalty payments. The pages I read do not mention paying a second person or splitting a payment, and KDP’s payment options page is silent on it too.

So if the book is published from your account, the royalties arrive in your bank account. Passing your co-author their share is something you do yourselves.

How do we split the royalties?

This is my advice, not KDP’s. Agree on the percentage before you start, and write it down. An equal split is one option, but it can instead reflect who writes, who pays for the cover and editing, and who does the marketing.

Then decide how the money moves. The simplest way is for the account holder to pay the co-author their share on a set schedule, with the royalty report as the record. KDP pays about 60 days after the end of the month of the sale, according to section 5.4.2 of the Terms and Conditions, so say in your agreement whether payments to each other follow that timing.

If you would rather not move money by hand, some platforms split payments for you:

• Draft2Digital. Its FAQ says “Yes, Draft2Digital supports payment splitting for collaborative projects, omnibus, or boxed sets!” Every collaborator needs a Draft2Digital account, a payment method and a completed tax interview. You can split print and ebook, or just one format.
• PublishDrive Abacus. PublishDrive describes Abacus as its royalty management and splitting service. Check their page for what it covers and what it costs.

What if my illustrator wants a share of the royalties?

KDP pays only the account holder, so a royalty share with an illustrator is a private deal. You track the sales and pay their share yourself, as the split section above describes.

A flat fee with a written agreement is simpler. That is my advice, not a rule, and it avoids tracking payments for years.

Ownership needs paper too. The US Copyright Office’s Circular 30 lists “pictorial illustrations” as an example of a “supplementary work.” A commissioned supplementary work can be a work made for hire only “if the parties expressly agree in a written instrument signed by them that the work shall be considered a work made for hire.” Without that, it is not a work made for hire.

Also say in the agreement whether you may use the art on merchandise, in ads or in later editions. This is not legal advice, and a lawyer has the final word.

What does copyright say about a book two people write?

In the US Copyright Office’s Copyright Basics, the copyright in a work “initially belongs to the author(s) who created that work.” When two or more authors create a single work “with the intent of merging their contributions into inseparable or interdependent parts of a unitary whole,” they are joint authors and “have an indivisible interest in the work as a whole.”

That is the US rule. Other countries differ, and I am not a lawyer. If the book matters to your business, have a lawyer check your agreement, and do not rely on this page for legal advice.

What if my co-author lives in another country?

KDP’s tax information page says Amazon requires all publishers to provide valid taxpayer identification. For authors outside the US it says a TIN is not needed to complete the tax questionnaire, though a reduced treaty withholding rate depends on providing one. The page does not mention more than one author or splitting for tax purposes. If you are outside the US, my walk through of the KDP tax interview for authors outside the US shows each step.

If one of you lives abroad, the payment from the account holder to the co-author may have tax effects in either country. I cannot tell you what they are, so ask an accountant before the first payment.

What should be in the co-author agreement?

I would cover these points in writing before launch:

1. The royalty split, and whether it is the same for ebook, paperback and audio.
2. Who owns the KDP account, and who is paid.
3. Who pays for the cover, editing and formatting, and whether those costs come off the top.
4. Who does the marketing, and who owns the email list the book builds.
5. What happens if one of you wants to leave, or the book is republished under a new title.
6. Whose name goes first, and how you will both be named in the book description.

A short agreement you both signed is better than a long one you never wrote.

What I do about it

If you are writing with a partner or colleague, for example to grow a business (see self-publishing for business owners), and want to get the setup right the first time, I can talk it through with you in a free 25-minute call. Book your free call.

Free 25-minute self-publishing call with Chris Baird

Tell me where your book is now. You leave the call with a clear next step for publishing it.

Book your free call

Free, 25 minutes on Zoom, no card needed.