CPA Calculator
Cost per acquisition, or CPA, is the average cost of generating one conversion from a campaign. It is the workhorse efficiency metric in performance marketing because it ties spend directly to outcomes, whether those outcomes are purchases, signups, or any other action you have defined as a conversion. This free cost per acquisition calculator returns your CPA from spend and conversions, and it requires no email.
Enter your numbers to see results.
The calculator also works backward. Switch modes and enter your average order value and gross margin to derive a break-even CPA, the most you can pay per conversion before a sale stops being profitable. That turns CPA from a backward-looking report into a forward-looking guardrail for how hard you can bid.
Use it to compare channel efficiency, set bid targets, or check a live CPA against the ceiling your margins can actually support.
How it works
CPA equals total ad spend divided by the number of conversions in the same period. A conversion is whatever action you are measuring, so define it consistently before comparing campaigns.
Break-even CPA equals average order value multiplied by gross margin. It is the contribution a sale produces, which is the most you can spend acquiring it before the order loses money. Bidding below break-even CPA protects first-order profitability.
Worked example
Suppose a campaign spends $5,000 and drives 125 conversions. CPA is 5,000 divided by 125, or $40 per acquisition.
To find the ceiling, take an $80 average order value at a 60% gross margin. Break-even CPA is 80 multiplied by 0.60, or $48. Acquiring a customer for more than $48 loses money on the first order, so the $40 CPA above clears the bar with room to spare.
What is a good CPA?
A good CPA is any CPA below your break-even CPA, because that is the only threshold tied to your actual economics. There is no universal target: a $40 CPA is excellent on an $80 order with healthy margin and ruinous on a low-priced, thin-margin product. Derive your break-even CPA from order value and margin first, then judge live CPA against it.
Watch direction more than the absolute value. For most consumer brands, a blended CPA under one-third of lifetime value is a healthy ratio, but rising CPA with stable LTV is the early signal of a broken funnel or an exhausted audience. A snapshot tells you less than a trend.
Compare payback windows, not just CPA snapshots. Two channels with the same CPA are not equal if one recovers its cost in weeks and the other takes months. Read CPA alongside conversion rate and margin, and benchmark it against QRY's monthly paid media benchmarks rather than a generic industry average.
See QRY's monthly paid media benchmarks to compare your numbers against the portfolio.
Frequently asked questions
What is a good CPA?
A good CPA is any CPA below your break-even CPA, which you derive from average order value and gross margin. There is no universal number; a $40 CPA is strong on a high-margin $80 order and unsustainable on a thin-margin product. For most consumer brands, a blended CPA under one-third of LTV is a healthy ratio.
How do you calculate cost per acquisition?
CPA equals total ad spend divided by the number of conversions in the same period. For example, $5,000 in spend across 125 conversions is a $40 CPA. Define your conversion event consistently so campaigns are compared on the same basis.
What is the difference between CPA and CAC?
CPA measures the cost of any defined conversion, which may be a lead, signup, or first action. CAC measures the cost to acquire a paying customer and is usually fully loaded with agency fees, tools, and sales costs. A campaign can have a low CPA on signups while its CAC for actual buyers is much higher.
How do I find my break-even CPA?
Break-even CPA equals average order value multiplied by gross margin. An $80 order at 60% margin gives a break-even CPA of $48, the most you can spend per acquisition before the first order loses money. Bidding below that figure protects first-order profitability.
Why is CPA trend more important than the absolute value?
A single CPA number tells you little without context, but its direction reveals funnel health. Rising CPA with stable LTV is an early sign of audience exhaustion or a leaking funnel, while falling CPA signals improving efficiency. Track the trend and compare payback windows, not just point-in-time snapshots.
Related calculators
Is your CPA below your break-even line?
Compare your acquisition costs to QRY's managed portfolio with our monthly paid media benchmarks.
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