Advertising dashboards report revenue, and revenue is not what an author keeps. A campaign showing a healthy return against cover price can still be losing money once the platform's share is removed, and that gap is wide enough that plenty of books are advertised at a quiet loss for months.
This calculator settles a campaign that has already run rather than forecasting one that has not. You enter what you actually spent and how many copies actually sold, and it works from royalty rather than list price to produce profit, return on spend, cost per sale, and the number of copies that spend needed in order to break even.
Worked example, using this calculator on 50 of spend against a 9.99 book earning the higher ebook rate, with ten copies sold. Royalty per copy is 6.99, so earnings are 69.93 and profit is 19.93 — a 39.9 per cent return, a cost per sale of 5.00, and a break-even point of eight copies. The same campaign measured against gross revenue of 99.90 would have looked considerably healthier than it was.
The two use different denominators. Ad platforms divide spend by the revenue a sale generated at cover price; this divides it by the royalty that actually reaches you, so the percentage is larger. Only one of them tells you whether you made money.
No. It settles campaigns that have already run, so it is the wrong tool for building a budget from scratch. Forecasts based on assumed click and conversion rates end up dominated by whichever assumption was most optimistic.
It depends on what the campaign is for, so the calculator reports the figure instead of grading it. A first book in a series can rationally run at a loss if later volumes earn it back, while a standalone title has to pay for itself in the same window.