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How to Calculate Break-even CPA
Every ad platform reports a CPA, but a CPA only means something next to one number: your break-even CPA — the most an order can bear before profit hits zero. Know it and you can tell at a glance which campaigns make money and which quietly burn it.
Here's how to calculate it, and how to turn it into a daily decision rule.
Break-even CPA Calculator
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Price and per-order costs — results update instantly.
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Avg per order
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Break-even CPA
58.5% margin$29.24
the most you can pay to win an orderTarget CPA
$21.24
leaves your target profitContribution / order
$29.24
before ad spendThe break-even CPA formula
Break-even CPA = selling price − all variable costs per order (product cost, shipping, payment fees, a returns allowance). Whatever contribution is left per order is the most you can spend to acquire it and still break even.
Example: a $49.99 product with $20.75 of variable costs has a $29.24 break-even CPA. Pay less and you profit; pay more and you lose.
Break-even CPA vs target CPA
Break-even CPA is the zero-profit line. Target CPA is lower — it leaves the profit you actually want per order. If you want $8 profit per order in the example above, your target CPA is $21.24. Use break-even as the hard ceiling and target as the goal.
Using it to judge campaigns
Compare each campaign's actual CPA to your break-even. Anything above it is losing money regardless of what the platform's ROAS column says. Because ad platforms double-count conversions, also sanity-check with your blended CPA and MER across all channels.
Frequently asked questions
Is CPA the same as CAC?
Closely related. CPA is usually the cost per order or conversion; CAC is the cost per customer, who may buy again. For a first order they're often used interchangeably.
What's a good CPA?
One comfortably below your break-even CPA. There's no universal number — it depends entirely on your margin.
Why can a campaign with good ROAS still lose money?
Because ROAS ignores costs. A CPA under the platform's target can still be above your break-even if your margin is thin.
Track this on a live dashboard
Connect your store and watch these numbers update themselves — no spreadsheets.
Keep reading
The Complete Guide to E-commerce Profitability
Revenue is vanity; profit is sanity. Walk the profit ladder — gross, contribution and net — learn which costs belong where, how discounts, shipping and returns bite, and how to find the numbers that tell you if you're actually making money.
Gross Margin vs Contribution Margin vs Net Margin
Three margins, three jobs. Learn what gross, contribution and net margin each measure, the formula for each, and which one to use for pricing, product decisions and judging the whole business.
What Is a Good ROAS? Break-even ROAS Explained
A “good” ROAS isn't a fixed number — it depends on your margin. Learn the ROAS formula, how to find your break-even ROAS, and how ROAS relates to ACoS, with a calculator to find yours.