Max CPA Calculator
Free max CPA calculator — find the highest cost per acquisition (also called break-even CPA) you can afford before ads lose money. Max CPA equals contribution margin per conversion: a purchase cap for ecommerce, or max cost per lead in lead gen mode. No signup.
Quick answer
Use this free max CPA calculator to find your break-even CPA — the highest cost per acquisition (or cost per lead) you can afford. Max CPA (maximum cost per acquisition) is the highest amount you can pay for one conversion and still break even. It equals contribution margin per conversion. Enter AOV and margin for your Target CPA ceiling.
Max CPA = contribution per conversion
Maximum affordable CPA
What is max CPA?
Max CPA (maximum cost per acquisition) is the highest amount you can pay for one conversion and still break even. It equals contribution margin per conversion. Spend above max CPA and every sale or lead loses money, even when platform ROAS looks fine.
Read the full explainer in Max CPA Explained for Ecommerce or the How to Set Target CPA guide.
Break-even CPA = max CPA
Searchers often look for a break-even CPA or CPA breakeven ads calculator. That number is the same as max CPA from this calculator: contribution per conversion after margin and fixed costs. If your live CPA sits above that ceiling, the campaign loses money after product costs — even when ROAS looks acceptable.
Use the result as a Target CPA ceiling in Google Ads or Meta, or as a benchmark for cost per purchase / cost per lead reporting.
Max CPA formula
Max CPA = (value × margin%) − fixed cost
Ecommerce: value is AOV and fixed cost is per order — this is your max CPA per purchase. Lead gen: use customer value × close rate as value and fixed cost per lead — the result is max cost per lead.
Max CPA vs target CPA
- Max CPA — break-even ceiling from your margin and costs. Do not bid above it.
- Target CPA — the bid goal you enter in Google Ads or Meta. Set it at or below max CPA if you want profit, not just break-even.
Ecommerce example
- AOV = $90
- Gross margin = 50%
- Fixed cost per order = $6 (shipping + payment fees)
Contribution = ($90 × 50%) − $6 = $39
Max CPA: $39 per purchase. Enter this as a Target CPA ceiling in Google Ads or benchmark Meta cost per purchase against it.
Max cost per lead calculator (lead gen)
For lead gen, this max CPA calculator is your max cost per lead calculator. Toggle lead gen mode, enter customer value, close rate, margin, and any fixed cost per lead. The result is max cost per lead — not max cost per closed deal.
Max cost per lead = (customer value × close rate × margin%) − fixed cost per lead
CRM closed-deal cap = max cost per lead ÷ close rate. Compare ad platform cost per lead to the calculator result; use the closed-deal cap only in your CRM or sales reporting.
Lead gen example
- Customer value = $5,000
- Close rate = 15%
- Gross margin = 60%
- Fixed cost per lead = $0
Expected revenue per lead = $5,000 × 15% = $750
Max cost per lead = $750 × 60% = $450
CRM closed-deal cap = $450 ÷ 15% = $3,000 max cost per closed deal.
When to use max CPA vs break-even ROAS
- Max CPA — when you bid or report on cost per conversion (Target CPA, cost caps, Meta cost per purchase).
- Break-even ROAS — when you optimize on return on ad spend (Target ROAS). Same economics, different unit. Use the Break Even ROAS Calculator or Target ROAS Calculator to set a floor plus buffer. Also see how to calculate break-even ROAS.
- Max CPC — turn max CPA into a click bid with the Max CPC Calculator.
How to use max CPA in Google Ads and Meta
After you calculate max CPA, set Target CPA at or below that ceiling so average cost per conversion stays profitable. Pair with the max CPA ecommerce guide and compare units in ROAS vs ROI vs CPA. For keyword bids, convert max CPA to max CPC using your conversion rate.
People also ask about max CPA
What is max CPA?
Max CPA (maximum cost per acquisition) is the highest amount you can pay for one conversion and still break even. It equals contribution margin per conversion.
Is break-even CPA the same as max CPA?
Yes. Break-even CPA and max CPA are the same number: contribution margin per conversion. This max CPA calculator returns that break-even ceiling for ecommerce purchases or lead gen cost per lead.
How do you calculate max CPA?
Max CPA = (value × gross margin %) − fixed cost per conversion. For ecommerce, value is AOV. For lead gen, value is customer value × close rate.
What is max CPA vs target CPA?
Max CPA is your break-even ceiling. Target CPA in Google Ads or Meta should usually sit at or below max CPA so you leave room for profit and variance.
What is a good max CPA for ecommerce?
There is no universal good max CPA — it equals your contribution per order. A $90 AOV at 50% margin with $6 fixed costs has a $39 max CPA. Use your own margin and costs.
How does max CPA relate to break-even ROAS?
They are the same economics in different units. Max CPA is contribution per conversion in dollars. Break-even ROAS is AOV ÷ contribution. Raising max CPA lowers break-even ROAS.
How do I get max cost per lead for lead gen?
Toggle lead gen mode, enter deal value, close rate, margin, and any fixed cost per lead. The result is max cost per lead — divide by close rate for a CRM closed-deal cap.