CPA Calculator
Enter your ad spend and conversions to get your cost per acquisition, or solve for the conversions or budget you need. Add order value and margin to see your break-even CPA and ROAS.
Total cost over the period you’re measuring.
Purchases, leads, or sign-ups over the same period.
Check against your margin
Revenue per conversion.
After product and fulfillment costs.
Your cost per acquisition
$50
$1,000 ÷ 20 conversions = $50 each
- Revenue
- $2,400
- ROAS
- 2.4×
- Break-even CPA
- $48
- Profit after ad spend
- -$40
Conversions you’d get for $1,000 at other CPAs
Illustrative CPA points, not benchmarks.
| CPA | Conversions | Profit per order after ads |
|---|---|---|
| $10 | 100 | $38 |
| $20 | 50 | $28 |
| $30 | 33.3 | $18 |
| $40 | 25 | $8 |
| $50your CPA | 20 | -$2 |
| $75 | 13.3 | -$27 |
| $100 | 10 | -$52 |
| $150 | 6.7 | -$102 |
Works for purchases, leads, sign-ups, and installs on any platform that reports spend and conversions. Free, instant, no sign-up.
How to calculate CPA
Cost per acquisition is spend divided by conversions. The same relationship solves for the conversions a budget will buy, or the budget a conversion target needs.
Cost per acquisition
CPA = Spend ÷ Conversions
$1,000 ÷ 20 = $50
Use this to see what each purchase, lead, or sign-up actually cost in a campaign or channel.
Conversions from a budget
Conversions = Spend ÷ CPA
$1,000 ÷ $50 = 20
Use this to forecast results before you launch, at the CPA your account has been delivering.
Budget for a conversion goal
Spend = CPA × Conversions
$50 × 100 = $5,000
Use this to size a budget when you are planning against a sales or lead target.
Worked example
You spent $1,000 and made 20 sales, so your CPA is $50. At a $120 average order that is $2,400 of revenue and a 2.4× ROAS. At a 40% gross margin each order earns $48 before ads, so your break-even CPA is $48 and the campaign lost about $2 per order.
What is a good CPA?
There is no universal good CPA. It depends on what a conversion is worth to you, which is why the calculator asks for average order value and gross margin. Gross profit per order is your break-even CPA: pay less than that and the first purchase is profitable; pay more and you are buying customers at a loss that only repeat purchases can recover.
That reframes most CPA questions. A $50 CPA is excellent for a $300 product with 60% margins and terrible for a $40 product with 30% margins. Rather than comparing to industry averages, compare to your own break-even and to the lifetime value of a customer.
CPA also rises with scale. The first dollars reach the most likely buyers; later dollars reach people who are harder to convince. Expect marginal CPA to climb as you increase budget and plan your target with that curve in mind.
How to judge your CPA
Compare to break-even CPA (order value × gross margin), not to a benchmark article.
Use lifetime value, not first-order value, for subscriptions and repeat-purchase products.
Check the conversion definition: a purchase CPA and an add-to-cart CPA are not comparable.
Look at marginal CPA as you scale, not just the blended average.
Watch the trend: a CPA climbing on stable spend usually means creative fatigue.
How to lower your CPA
CPA falls when more of your impressions turn into results. These are the levers that move it most on Meta.
Refresh creative before it fatigues
New hooks and formats keep engagement and conversion rates high as frequency builds.
AI Image AdsBuild campaigns from your winners
Start every campaign from the audiences, creatives, and copy that have already converted.
AI Campaign BuilderTest hundreds of combinations
Find the creative-audience-copy combination with the lowest CPA by testing at scale.
Bulk Ad LaunchOptimize around the clock
Move budget toward the ad sets converting cheapest and away from the ones drifting above target.
AI Media BuyerCPA Calculator FAQ
Keep reading
Guides from the AdStellar blog that go deeper on this topic.
How to reduce CPA on Facebook ads
A step-by-step guide to lowering cost per acquisition without losing volume.
Read the guideCPA on Facebook: what it means and how to lower it
The metric explained, with the benchmarks that actually matter.
Read the guide8 proven strategies to fix high CPA on Facebook ads
What to change first when cost per acquisition climbs above target.
Read the guideCan AI lower my cost per acquisition on Meta ads?
Where AI optimization moves CPA and where it does not.
Read the guideMore free tools
Bring your CPA under break-even
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