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CPA Calculator

Spend and conversions give you CPA. Add order value and margin to see the maximum CPA before a campaign loses money.

Free toolsPaid MediaReviewed September 2026

Spend and conversions

Media cost only, before agency or platform fees.

Orders, leads, or sign-ups, as long as you use one definition.

Add clicks to see conversion rate and CPC.

Break-evenThe most you can pay per conversion before it loses money.

Revenue per conversion.

After cost of goods or delivery.

CPA

–

Spend ÷ conversions

Conversion rate
–
Needs clicks
CPC
–
Needs clicks
Break-even CPA
–
Order value × margin
Headroom
–
Break-even − CPA
Profit per conversion
–
After ad cost
Campaign gross profit
–
After ad spend

Runs entirely in your browser. Nothing you enter is stored or sent anywhere. Last reviewed September 2026.

CPA only means something next to break-even

Cost per acquisition is the price you pay for a customer. Break-even CPA is the price you can afford. The first number comes from the ad platform. The second comes from your P&L: what a conversion is worth after the cost of delivering it. A $50 CPA is excellent for a $400 order at 50% margin and ruinous for a $60 order at 40%.

The tool computes CPA as spend divided by conversions, then computes break-even as average order value multiplied by gross margin. The difference is your headroom, which is also the gross profit each conversion leaves behind after paying for the ad. Add clicks and it fills in conversion rate and CPC, so you can see whether a high CPA comes from expensive clicks or a landing page that does not convert.

Two cautions. Gross margin should reflect everything that scales with the sale, including shipping, payment fees, and returns, or the break-even will flatter you. And if customers buy again, a single-order break-even understates what you can pay. Use expected lifetime gross profit in the order value field for that case, and be conservative about retention.

Formulas

CPA
= Spend ÷ Conversions
Conversion rate
= Conversions ÷ Clicks
CPC
= Spend ÷ Clicks
Break-even CPA
= Average order value × Gross margin
Headroom
= Break-even CPA − CPA
Profit per conversion
= Order value × Gross margin − CPA
Campaign gross profit
= Profit per conversion × Conversions

Frequently asked questions

How do you calculate CPA?

Cost per acquisition is total ad spend divided by the number of conversions that spend produced. $5,000 that generates 96 conversions is a CPA of $52.08. Be consistent about what counts as a conversion: a lead, a trial, and a paid order are very different events, and a CPA is only comparable across campaigns when the conversion definition is the same.

What is break-even CPA and how do I find it?

Break-even CPA is the most you can pay for a conversion before the sale loses money. It is average order value multiplied by gross margin. A $120 order at 60% gross margin contributes $72, so any CPA above $72 means the campaign is paying more for the customer than the sale earns. For subscription businesses, use expected gross profit over the customer lifetime instead of a single order, and be honest about churn.

Should I set my target CPA at break-even?

No. Break-even covers the cost of goods but nothing else: no salaries, tools, agency fees, returns, or payment processing. Most teams set a target CPA well inside break-even so each conversion contributes to overhead and profit. The headroom figure above shows how much room you have. If it is negative, the campaign needs a higher order value, a better margin, a cheaper conversion, or a stop.

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