Amazon ACoS calculator

How each number is calculated

These are the definitions Amazon Ads uses in its ACoS guide.

• ACoS (advertising cost of sales) = ad spend ÷ ad sales × 100. Spending $50 to generate $100 of ad sales is a 50% ACoS.
• ROAS (return on ad spend) = ad sales ÷ ad spend. It is the inverse of ACoS, so a 50% ACoS is a ROAS of 2.
• TACoS (total advertising cost of sales) = ad spend ÷ total sales × 100. It shows how much advertising your whole business depends on.
• Break-even ACoS = your profit margin before advertising: (selling price − cost per unit) ÷ selling price × 100. Below it, ad-driven sales make a profit; above it, they lose money.

How to read the result

There is no single good ACoS. A product with a 40% margin can run a 30% ACoS profitably, while the same ACoS loses money on a product with a 20% margin. That is why the calculator compares ACoS with your own break-even point rather than an industry average.

Running above break-even is sometimes a deliberate choice during a launch, when you are paying for sales velocity and reviews. Set an end date and a target for that phase. If TACoS keeps rising while total sales stay flat, your advertising is replacing organic sales rather than adding to them.

The result covers advertising only. Storage, returns, overheads and tax are not included, so leave a margin of safety below break-even.

Bring the number down

Our guide on how to lower Amazon ACoS covers negative keywords, campaign structure, placement bids and conversion fixes. You can find definitions of every metric in the glossary, try the free Amazon keyword tool, and see how we run Amazon PPC management for brands.