Facebook Ads CPA Calculator

CPA on Meta (Facebook & Instagram)

Meta's 'cost per result' depends on the optimisation event and the attribution setting. A campaign optimised for purchases with 7-day click / 1-day view attribution reports more purchases — and a lower CPA — than the same campaign measured on 7-day click only. Pick one attribution setting for your whole account and compute CPA here from spend and that consistent conversion count.

Break-even CPA = revenue per conversion × contribution margin. For lead campaigns, revenue per conversion is expected value per lead (deal value × close rate), which turns a cost-per-lead target into something defensible. Meta's cost cap bid strategy takes exactly this number: set it a little below break-even, and delivery stops when the auction can no longer find conversions at that price.

Formula

CPA = Ad spend ÷ Conversions
Break-even CPA = Revenue per conversion × Gross margin
Profit per conversion = Break-even CPA − CPA

How to read CPA

Cost per acquisition is what one conversion cost you in media. It is the most direct efficiency metric for campaigns whose goal is a countable action — a purchase, a lead, an install — and the number you bid against when using target-CPA strategies.

The figure that matters more is break-even CPA: the gross profit one conversion brings in. Any CPA below it makes money on the first order; above it you are paying for growth and need repeat purchases (LTV) to justify it. Set target CPA as a fraction of break-even, not as a round number.

Frequently asked questions

Should I use cost cap or bid cap for CPA control?

Cost cap keeps average cost per result at or below your number and lets Meta spend where it can; bid cap limits the maximum bid per auction and often restricts delivery. Start with cost cap at your break-even CPA minus a margin of safety.

Why is CPA higher for new customers than in reporting?

Reported CPA blends returning customers, who convert cheaply, with new ones. Advantage+ shopping campaigns can cap existing-customer spend so the reported CPA reflects acquisition. Compare against CAC from the CAC Calculator for the full picture.

CPA or CPL — what is the difference?

Same formula, different conversion. CPL (cost per lead) counts form fills or sign-ups; CPA usually counts paying customers. For lead-gen, use lead value (average deal value × close rate) as the revenue per conversion to get a meaningful break-even.

Why is my platform CPA lower than this?

Platforms count conversions with their own attribution windows and may include view-through conversions. Calculating CPA from your own order or CRM data with the platform's spend gives the real figure.

How does target CPA relate to ROAS?

They are two views of the same target: Target ROAS = Revenue per conversion ÷ Target CPA. A $120 order with a $40 CPA target is a 3.0× ROAS target.