What Is CPA (Cost Per Acquisition): How to Calculate and Optimise It

What CPA Means in Marketing

CPA (Cost Per Acquisition) is the average amount spent on advertising to obtain one valuable action: a sale, qualified lead, booking, or app download. Formula: CPA = Total ad spend / Number of acquisitions.

How to Calculate Your Target CPA

Target CPA = Average customer value × Gross margin × % of gross profit you accept for acquisition. Example: €60 average order, 40% margin, willing to invest 30% of gross profit → Target CPA = 60 × 0.40 × 0.30 = €7.20. Including LTV (customer buys 3 times): target CPA = €21.60.

CPA vs. CPL

CPL measures cost to get an interested contact. CPA measures cost to get a real customer. CPA = CPL / lead-to-client conversion rate. If CPL is €10 and 1 in 5 leads becomes a client, real CPA is €50.

What Reduces CPA in Google Ads

Improve Quality Score, eliminate high-cost low-conversion keywords, use Target CPA bidding (after 30–50 conversions), improve landing page conversion rate, segment campaigns by purchase intent.

What Reduces CPA in Meta Ads

Improve creative quality (on Meta, creative matters more than audience), optimise on the right event (if under 50 weekly purchases, optimise on Add to Cart), expand performing Lookalike audiences, consolidate campaigns for more data per budget.