You and a co-author agreed on a 50/50 split. It was the easiest conversation you've ever had about money. Fair, simple, done — back to writing.
Then the book started earning. Across KDP and IngramSpark and ACX and Draft2Digital, in dollars and pounds, with returns drifting in three months after the original sale. And somewhere around the second or third quarter, "50/50" stopped being a number and started being a question. Fifty percent of what, exactly? Gross or net? Before or after currency conversion? Based on this month's report or this month's deposit? Before or after that return from March that just showed up in June?
These aren't hypothetical. They're the questions that quietly strain creative partnerships — not because anyone's being dishonest, but because nobody thought to answer them when the answer was still easy.
Last week I wrote about the private anxiety that your own numbers might be wrong. This is the version of that anxiety that faces outward. When the money is shared, fuzzy numbers don't just worry you. They can hurt someone you care about. The stakes aren't just financial anymore. They're relational.
The five questions "50/50" doesn't answer
Most co-author agreements skip these entirely. Not out of carelessness — out of optimism. You trusted each other enough to write a book together. Surely you trust each other enough to split the money fairly. And you do. The problem isn't trust. The problem is that "fairly" means different things when nobody's defined it.
Gross or net? Does 50% mean half of what the distributor reports as your earnings, or half of what actually lands after their fees? KDP takes 30% on books priced outside the $2.99–$9.99 band, 35% on some formats. IngramSpark's wholesale discount structure means the "list price" and the "your share" number are very different things. If you've never said which number the split applies to, both of you are doing math against a different starting point.
Whose exchange rate? Your book earned £847 in the UK last quarter. In whose dollars? The distributor converted at one rate. Your bank will convert at another. And if you're the one pulling numbers into a spreadsheet, you probably used xe.com on whatever Tuesday you got around to it. Over a year of international sales, those three rates can disagree by hundreds of dollars. Neither of you did anything wrong. You just never decided whose rate wins.
When do returns come out? A customer returns a copy in June for a sale that happened in March. Does that return reduce June's split, or does it retroactively adjust March's? Both approaches are defensible. Neither is obvious. And if the two of you are using different assumptions, one person's running total will quietly diverge from the other's.
What's the payment schedule? Monthly? Quarterly? "When I get around to it"? Silence on this breeds quiet resentment faster than almost anything else in a creative partnership. Not because the money is urgent — most co-author shares aren't life-changing quarter to quarter — but because the silence itself starts to feel like something's being avoided.
Who does the math, and how does the other person verify? One of you pulls the reports, runs the calculations, and sends a number. The other trusts it. That's a lot of trust, and it's asymmetric. It doesn't mean anyone's being dishonest. It means the person receiving a number has no way to feel confident in it without asking questions that feel like accusations. A split without a visible paper trail asks one party to simply believe — and that's an unfair thing to ask of someone indefinitely.
Why this strains good partnerships
The reason these questions go unasked isn't laziness. It's that raising money specifics in a creative relationship feels like introducing distrust. You don't want to be the person who turns a collaboration into a contract negotiation. So you leave it vague, and the vagueness does exactly what you were afraid the conversation would do: it plants doubt where there used to be none.
If you're the one paying the split, you worry that you're doing it wrong and don't know it. If you're the one receiving it, you wonder whether the number you're getting is the right one but can't ask without it sounding like you think your partner is cheating you. Both sides carry the uncertainty. Neither side talks about it. The partnership quietly accumulates weight it was never designed to hold.
The one-page agreement: five things to write down before you split a dollar
This is not legal advice. It's operational clarity — the document that prevents the "wait, I thought we agreed…" conversation six months from now. Both people should have a copy. It takes fifteen minutes to fill out and it's written to read fairly from either side of the split.
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The split percentage and what it applies to. State the percentage and confirm it applies to net earnings after distributor fees, per edition. If the split differs by format or by title, say so here.
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The currency conversion method. Name the source and the timing. Example: "xe.com mid-market rate on the last day of the reporting period." Doesn't matter which source you pick. What matters is that you both know which one it is.
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How returns are handled. Deducted from the period they appear in, noted as a line item on the statement. No retroactive adjustments to prior periods unless both parties agree.
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Payment schedule and method. Example: "Quarterly, within 30 days of the period close, via bank transfer." Pick a rhythm you can actually keep. Quarterly is manageable for most indie publishers and frequent enough that neither party is left wondering.
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What a statement looks like. Both parties receive a line-by-line breakdown showing distributor, title, gross earnings, conversion rate, net earnings, and their calculated share. Not just a total and a bank transfer. The statement is the trust document — it's what makes everything above verifiable.
That's it. Five items, one page, both signatures. You can draft it over coffee. The hard part isn't writing it — it's starting the conversation. But starting it now, when everything is fine, is a thousand times easier than starting it later, when something feels off.
How Royaltally handles this part
I built Royaltally because I was the person doing the math by hand, worrying I'd got it wrong, and knowing that the person on the other end had no way to check.
The system handles per-edition percentage splits automatically, calculated from the parsed distributor reports. Each royalty holder gets a statement showing every line — which distributor, which title, gross amount, conversion rate applied, net amount, their share. Both parties review the same numbers from the same source data. The agreement template above still matters even with software — the tool calculates the split, but you still need to agree on what the split means.
Royaltally is in open beta right now. If you're splitting royalties with a co-author and want to see what that looks like with your own reports, you can try it free with up to 3 titles at royaltally.com.
Protect the partnership
The money part of a co-authorship is never the part either of you got into it for. But getting clear on it — even just a one-page agreement and a quarterly rhythm — is what keeps the money from becoming the thing you think about when you should be thinking about the next book.
You didn't start writing together so you could argue about exchange rates. Write the five things down, pick a schedule, and give both of you the gift of never having to wonder.
Next week I'm going into the currency conversion question in detail — because the gap between what your distributor says you earned in GBP and what actually lands in your USD account is bigger than you think.