Estimate the clicks, sales and daily spend required for a controlled Amazon Ads test. The calculator also shows the maximum average CPC that fits your royalty, conversion rate and target ACOS.
Use conservative estimates for a new campaign. This is a planning model, not a promise of sales.
The calculator starts with your target sales and expected conversion rate. If you expect 10% of ad clicks to convert and want two sales per day, the model estimates that you need about 20 clicks. It then multiplies those clicks by your expected CPC to produce a daily spend estimate.
The maximum CPC is a separate guardrail. It is calculated from book price, target ACOS and conversion rate. Your royalty determines the break-even ACOS, while a stronger conversion rate gives the campaign more room to bid. A low conversion rate sharply reduces the CPC you can afford, even when the daily budget looks reasonable.
Suppose a paperback sells for $9.99 and earns a $3.50 royalty. Its basic break-even ACOS is about 35%. With a 30% target ACOS, $0.40 expected CPC and a 10% conversion rate, two sales per day may require about 20 clicks and $8 in daily spend.
The target-ACOS daily spend would be about $5.99 and the maximum average CPC about $0.30. Paying $0.40 per click would therefore miss the 30% target unless the listing converts better than expected. The useful response is not simply to raise the budget: lower the bid, improve the cover and product page, target more relevant searches, or reconsider the target.
Use the customer-facing list price and the royalty after delivery or printing cost. Calculate the royalty first with the KDP Royalty Calculator.
This is the share of ad-attributed sales revenue you are willing to spend. It should stay below your royalty-based break-even point when direct profit is the goal.
Use a realistic estimate from your market or a conservative starting bid. Competitive keywords can cost more than long-tail, highly relevant searches.
New books often lack reliable data. Start cautiously and update the calculator after the campaign has collected enough clicks.
A larger target increases the number of clicks and total daily spend, but it does not change whether the underlying CPC is sustainable.
Amazon attribution, organic sales and Kindle Unlimited page reads can arrive on different schedules. Use settled reporting periods when deciding whether advertising is supporting the whole book rather than reacting to a single day's ACOS.
How much should a KDP author spend per day?
There is no universal amount. Base the first test on royalty, expected conversion, CPC and a clear sales target. Start small enough that poor early assumptions do not create an expensive lesson.
How is maximum CPC calculated?
The model multiplies book price by target ACOS and expected conversion rate. Royalty per sale is used separately to show the basic break-even ACOS.
What if expected CPC is above maximum CPC?
The campaign is unlikely to reach the selected target ACOS unless conversion improves, royalty increases or actual CPC falls. Reducing bids or improving the listing is usually more useful than raising the budget.
Should I include KENP income?
Not in this initial sales-budget calculation. Track KENP separately and reconcile it after the reporting period settles because page-read income may be delayed.
Does a higher daily budget improve ad performance?
No. It only permits more spend. Relevance, bid level, conversion and book economics determine whether that spend produces a sustainable result.
Royalty Calculator — calculate the per-sale margin before planning ad spend.
Ads Break-even Calculator — evaluate ACOS, TACOS, organic sales and settled KENP after a campaign is running.
KDP Pricing Calculator — compare pricing, royalty and upfront-cost recovery.
Free KDP resources — download the KENP Rate Report 2026.
Estimates only. Check Amazon Ads and KDP reports before changing bids or budgets. This calculator does not provide financial advice or guarantee sales.