Know exactly where your next marketing dollar should go
Most advertising tools tell you your ACoS. What you want to know is whether a reader you paid for earns back more than they cost — across your whole series.
Built on the data you already have
- Amazon Ads
- Kindle Direct Publishing
- Kindle Unlimited
- KDP royalty reports
The best way to spend an advertising budget
Every screen answers the same question in a different way. Open one and look around — this is the product, running on demonstration data.
Good morning, Elena
Here is where your advertising needs attention.
Estimated reader profit · last 30 days
Calculated−$229.86
Advertising is costing more than it returns. Attributed royalties minus advertising spend, excluding any projection.
Plus estimated series follow-on
Estimated+$2,701.74
Projected royalties as these readers continue through your series. A forecast, not earnings.
Advertising spend
Demo data$2,410.00
1,284 clicks
Attributed reader revenue
Demo data$2,180.14
Including $612.80 from Kindle Unlimited pages
Readers acquired
Demo data707
Purchases plus Kindle Unlimited borrows that earned a royalty
Cost per reader
Calculated$3.41
Below your break-even of $6.82, so each reader is bought at a profit.
Reader lifetime value
Calculated$6.82
Break-even at $6.82, target $5.12
Amazon revises attributed sales and pages read for up to 42 days, so the last few days of this window will still move.
What should I do today?
Each change is checked against your guardrails before it reaches Amazon.
Pause “free kindle books”
High confidence- What happened
- 188 clicks and $71.30 spent over 30 days, with no orders and no Kindle Unlimited pages read.
- Why it matters
- At a reader value of $6.82 this keyword cannot recover its cost, and the next 188 clicks will spend the same again.
- What to do
- Pause the keyword. Your other keywords keep running unchanged.
Raise the bid on “slow burn fantasy romance”
High confidence- What happened
- Nine orders and 41,200 pages read from 214 clicks, at $2.31 a reader.
- Why it matters
- That is well under your $6.82 break-even, and the keyword is losing impression share at the current bid.
- What to do
- Raise the bid from $0.42 to $0.48, a 14% increase and within your 15% single-change limit.
7 more suggestions, grouped by what they change.
Demonstration figures. Amazon Advertising API access is pending approval, so no live account is connected.
How it works
What the product reads, what it calculates, and what it is allowed to change.
Connecting an account
You authorise ReaderROI to read your Amazon Advertising account through Amazon’s official API, using Login with Amazon. We never ask for your Amazon password, and access can be revoked from your Amazon account at any time.
Your book economics
Advertising data alone cannot tell you whether a reader was worth acquiring. That needs your royalties and how readers move through your series, so you enter your books, their order, and what proportion of readers continue from one to the next.
What a reader is worth
Read-through compounds. If 65% of readers continue from book one to book two, and 45% of those go on to book three, then 29.3% of your original readers reach the third book — not 45%. Getting this wrong in either direction leads to bad spending decisions, so the product shows the arithmetic rather than presenting a number to be trusted.
Recommendations
Deterministic rules examine each keyword and search term against your evidence thresholds: pause candidates, bids worth raising or lowering, searches worth targeting properly, queries worth blocking. Each recommendation states what happened, why it matters, what to do, and how confident the conclusion is.
Changes to your account
Nothing is changed without you approving it. The product starts in Observe mode, where it analyses and recommends but never writes. Moving to Copilot lets you approve individual changes; each one is then checked against limits you set — maximum bid increase, maximum budget increase, minimum evidence before pausing, maximum changes per day, and campaigns you have marked protected.
Your data
Advertising data is used solely to produce analysis for the account it came from. Access credentials are encrypted and held on the server; they are never exposed to the browser. Authorisation is enforced in the database, so one account cannot read another’s data.
Decisions
Built to decide, not to dashboard
Most advertising tools hand you a chart and leave the judgement to you. This one reaches a conclusion, ranks it against everything else it could recommend, and tells you what it would change.
Each recommendation carries the evidence behind it and how confident it is — so you can disagree with it on the merits.
Worth doing today
Pause “free kindle books”
188 clicks · $71.30 · no orders
Raise bid to $0.48
$2.31 a reader against $6.82
Target “ash and ember book 2”
6 orders · 12,400 pages read
Hold “epic fantasy series”
96 clicks · 1 order · watch
Profit · last 30 days
Attributed royalties
$2,180.14
AttributedAdvertising spend
−$2,410.00
ObservedTrue profit
−$229.86
CalculatedSeries follow-on
+$2,701.74
EstimatedThe estimate is shown beside the profit figure, never inside it.
Provenance
Every number says where it came from
Observed, attributed, imported, entered by you, calculated, or estimated — each figure is labelled, with its currency and the days it covers.
A forecast of what your series will earn can never appear as money you have made. The headline profit figure excludes projections entirely.
Control
Nothing reaches your account without you
Approve a change and it is applied for you, checked first against limits you set: how far a bid may move, what may be paused, how much may be spent in a day.
Every change is recorded with the value it had before, so anything can be traced or undone. No language model computes a financial figure or touches an advertising account — models are used to explain the arithmetic, never to perform it.
Apply this change?
Keyword bid — “slow burn fantasy romance”
$0.42→$0.48
Within your 15% single-change limit
Keyword is not protected
Previous value recorded in the audit log
One reader, four books
| Book | Royalty | Reach | Contributes |
|---|---|---|---|
| Book one | $3.00 | 100% | $3.00 |
| Book two | $3.50 | 65% | $2.28 |
| Book three | $4.00 | 29.3% | $1.17 |
| Book four | $4.00 | 9.4% | $0.37 |
| What one reader is worth | $6.82 | ||
Read-through compounds: 45% of the 65% who reach book two is 29.3% of where you started, not 45%.
Reader value
A reader is worth more than the book they bought
If someone buys book one and 65% of those readers go on to book two, and 45% of those continue to book three, that reader is worth considerably more than one royalty. Advertising tools that only see the first sale will tell you to stop spending long before you should.
Judged on book one alone, paying $4 for a reader looks like a $1 loss. Judged properly, it leaves $2.82. ReaderROI does that arithmetic on every keyword, and shows its working.
What it will not do
An advertising tool that always finds something to recommend is a slot machine. These are deliberate.
It will tell you to spend nothing
If your book page is not converting, more traffic buys more of the same problem. The product says so rather than selling you a budget increase.
It will say when there is not enough data
A keyword with seven clicks is noise. Below a threshold you control, it declines to form an opinion at all.
It never presents a forecast as earnings
Projected series income is shown separately from royalties Amazon has actually attributed. The headline profit figure excludes all projections.
No AI decides how your money is spent
Every financial figure comes from tested arithmetic. Language models are used to explain those figures in plain English, never to produce them.
Pricing
A flat monthly fee. Not a percentage of your advertising spend — a tool paid out of a share of your budget has an interest in that budget growing, which is precisely the opposite of what this is for.
Free
Getting a feel for your numbers
$0per month
Get startedGo to your dashboard- One book
- Import your KDP royalty and advertising reports
- Reader lifetime value and true profit
- Daily recommendations you can read
- Observe mode only — nothing is applied for you
Early Access
Indie authors running Amazon Ads
$29per month
Try free for 14 daysGo to your dashboard- Campaign, keyword and search-term analytics
- Reader lifetime value and break-even acquisition cost
- True profit, with estimates kept separate from earnings
- KDP royalty report import
- Daily recommendations, each with its evidence
- Copilot — approve a change and it is applied for you
- Up to ten books, one Amazon marketplace
Pro
Authors with several books or a series
$99per month
Try free for 14 daysGo to your dashboard- Everything in Early Access
- Unlimited books and series
- Several Amazon marketplaces at once
- Longer performance history retained
Both paid plans start with 14 days free. No card is taken today — there is no payment flow yet, so nothing is charged when a trial ends.
Common questions
The things authors ask before they trust a tool with an advertising budget.
Can I connect my Amazon Advertising account today?
Not yet. Amazon Advertising API access is pending approval, so no live account can be connected. The product runs on demonstration data through the same interfaces a real connection will use, which is why every figure in the product carries a Demo data label.
What is free, and what does the 14-day trial cover?
The Free plan is permanent: one book, Observe mode, and your own figures from the KDP royalty and advertising reports you import. Early Access and Pro each start with 14 days free, which adds Copilot, search-term analysis and the rest of your catalogue. No card is taken today. Because a live Amazon connection is not possible yet, the analysis runs on the reports you import, with a demonstration account to explore before you import anything.
Where do my royalties come from, if Amazon has no API for them?
It has none for Kindle Direct Publishing, so sales and royalties are either imported from the report you download from KDP or entered by hand. Both are labelled as such, and something you typed is never shown as though Amazon reported it.
What if I do not know my read-through rates?
You can enter them, or let them be derived from your sales history. Until a book has a royalty and a read-through, reader lifetime value is marked incomplete and recommendations that depend on it are held back rather than computed from a guess.
Will it change my campaigns without asking?
No. It starts in Observe mode, where it analyses and recommends but never writes. Copilot applies only the individual changes you approve, and each one is checked first against limits you set — maximum bid increase, maximum budget increase, minimum evidence before pausing, maximum changes per day, and campaigns you have marked protected.
Does an AI decide how my money is spent?
No. Every financial figure comes from tested arithmetic in the analytics layer. Language models are used only to phrase those findings in plain English; they cannot calculate a value or originate an action.
Why do last week's numbers keep changing?
Amazon revises attributed sales and Kindle Unlimited pages read for up to 42 days. The product stores each revision rather than overwriting the previous one, so recent days will keep moving and the page tells you when they are still settling.
Is it useful if I only have one book?
Probably not. It needs enough advertising history to say something with confidence, and reader lifetime value is built from what a reader is worth across a series. A single unpublished book gives it nothing to work with.
How is it priced?
A flat monthly fee, never a percentage of your advertising spend — a tool paid from a share of your budget has an interest in that budget growing. There is a permanent free plan, and both paid plans start with 14 days free. No card is taken today: there is no payment flow yet, so nothing is charged when a trial ends, and you will be told the price before that changes.
Can I revoke access later?
Yes. Authorisation goes through Login with Amazon, we never ask for your Amazon password, and you can revoke access from your Amazon account at any time.
Who it is for
Independent authors and small publishers with a series or a meaningful backlist, already earning royalties, already spending on advertising, and with no wish to become full-time campaign managers. It needs enough history to say something useful — a single unpublished book will not give it anything to work with.
Current status
The free plan is open, and both paid plans start with 14 days free. No card is taken today. Amazon Advertising API access is still pending approval, so a live account cannot be connected yet — the analysis runs on the advertising and KDP royalty reports you import, with a demonstration account to explore first. Paid plans are not billable yet. Questions go to hello@readerroi.com.