Quick answer
Break-even ACOS is the highest advertising cost of sales an Amazon product can tolerate before ad-attributed orders become unprofitable. Calculate it from pre-ad profit divided by selling price, then compare that threshold with actual campaign ACOS from Amazon Ads.
How this calculator works
The calculator subtracts product cost, freight or FBA fulfillment, referral fees, return loss, and other non-ad costs from selling price. The remaining pre-ad profit divided by selling price is the break-even ACOS. Current ad cost per order is also shown so you can see whether the order still leaves profit after the ads you are already paying for.
Amazon Ads defines ACOS as ad spend divided by ad-attributed sales. CrossMargin uses that reporting metric with your unit economics to estimate a no-profit threshold; it is not an Amazon campaign recommendation. Confirm current product-specific fees with Amazon's fee and cost estimator and current campaign ACOS in your Amazon Ads reports. Page reviewed: July 28, 2026.
Decision table
| Actual ACOS result | Meaning | Next action |
|---|---|---|
| Below break-even ACOS | Ad-attributed orders likely leave contribution profit | Test controlled bid or budget expansion |
| Near break-even ACOS | Margin buffer is thin | Improve conversion, lower CPC, or reduce unit costs before scaling |
| Above break-even ACOS | Ad-attributed orders likely lose money | Cut wasted queries, add negatives, adjust price, or fix cost structure |
Related reading
Read the break-even ACOS formula guide for the full method, the Amazon ACOS benchmark guide for target-setting context, and the TACOS guide when total sales quality matters more than ad-attributed orders alone.
FAQ
How do I calculate break-even ACOS?
Break-even ACOS equals pre-ad profit divided by selling price. Pre-ad profit is selling price minus product cost, freight or FBA fulfillment, referral fees, returns, and other non-ad costs.
Is break-even ACOS the same as target ACOS?
No. Break-even ACOS is the no-profit threshold. Target ACOS should usually be lower so the product still keeps margin after advertising.
What should I do if actual ACOS is above break-even ACOS?
Reduce wasted clicks, tighten keywords and negatives, improve conversion, raise price, or lower unit costs before increasing budget.