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Break-Even ACoS & Max CPC Calculator

Find the highest ACoS and cost-per-click you can pay on Amazon PPC before an ad sale loses money, and the bid that still hits your profit goal.

Selling price ($) Product cost / COGS ($) Referral fee (%) FBA fulfillment fee ($) Other per-unit cost ($) Conversion rate (%) Target profit margin (%)

Break-even ACoS

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Enter your numbers above to see the result.

The detail behind it

Max CPC bid

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Target ACoS (for goal)

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Bid for profit goal

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How the math works

Break-even ACoS = profit before ads ÷ price, where profit = price − referral − FBA − other costs − COGS. It's the ad-spend share at which an ad sale breaks even.

Max CPC = price × ACoS × conversion rate. Target ACoS = break-even ACoS − your profit-margin goal; the bid for that goal uses the same CPC formula.

How break-even ACoS and max CPC work

ACoS (Advertising Cost of Sale) is ad spend divided by the sales those ads drove. Your break-even ACoS is simply your profit margin before ads: spend exactly that share of revenue on advertising and an ad-driven sale neither makes nor loses money.

The most you can bid per click follows from your conversion rate: max CPC = price × ACoS × conversion rate. Only some clicks convert, so a higher conversion rate supports a higher bid for the same ACoS.

To keep a profit margin rather than just break even, subtract that margin from your break-even ACoS to get a target ACoS, then bid for it. This calculator does all of that from your price, costs and conversion rate.

Frequently asked questions

What is a good ACoS on Amazon?

It depends on your margin. The benchmark is your break-even ACoS, which equals your pre-ad profit margin; a good ACoS sits comfortably below it so each advertised sale still profits.

What's the difference between break-even and target ACoS?

Break-even ACoS is where an ad sale makes zero profit (it equals your margin). Target ACoS is lower: break-even ACoS minus the profit margin you want to keep.

How is the max CPC bid calculated?

Max CPC = selling price × ACoS × conversion rate. At break-even ACoS it's the most you can pay per click without losing money; use the target ACoS to bid for a profit goal.

Why does conversion rate change my bid?

You pay per click but only some clicks convert. A higher conversion rate means more clicks pay off, so you can afford a higher cost-per-click at the same ACoS.

Is it free?

Yes, free with no signup; everything is calculated in your browser.