Free KDP royalty calculator
Free Amazon Ads break-even calculator
Amazon Ads break-even calculator: the ACOS where ads stop paying.
Ads can convert a profitable book into a losing one. Enter the price, the royalty you actually get, and your conversion rate to see exactly where that happens.
Checked:
✓Break-even ACOS in one number✓Max CPC the royalty supports✓Works with any royalty estimate
The one-liner formula
Break-even ACOS is your royalty divided by your price. Every cents-per-click bid above that number means the ad sale itself loses money, even when it looks like a sale.
Max CPC is even more useful: royalty per sale times conversion rate. Bid above that and each order costs more than the royalty pays you.
Keep it honest
The calculator never claims a ranking, an income, or a bestseller result. It computes the edge of profitability for your own numbers; Amazon's auction and your copy decide the rest.
FAQ
Frequently asked questions
What is a good ACOS for book ads?
A healthy target is anything at or below your break-even ACOS. For a typical $4.99 ebook with 70% royalty, that is around 70% before other costs.
Where do I get the royalty per sale?
Use the KDP royalty calculator for your exact list price and file size; delivery fees and the 35%/70% band are already included there.
Does this guarantee advertising profit?
No. It sets the arithmetic boundary. Copy, placement, and demand decide whether your ads sell at all.
Publish numbers you can defend.
The release pass produces the metadata and store copy your ads will point at — one version, one price, one description.