What is CPA?
Cost Per Acquisition: what you spend on advertising, on average, for one conversion such as a sale or a sign-up.
Calculate your CPA
More details
CPA is the core KPI for campaigns that optimise for sales or sign-ups. You calculate it by dividing your ad spend by the number of conversions. Whether a CPA is good depends on your margin: as long as the CPA is lower than what a conversion earns you, your ads make money. In Google Ads and Meta you can set a target CPA so the algorithm bids around that amount.
For example…
A web shop spends €4,000 on ads in a month and gets 80 orders from them. The CPA is €50. If the shop keeps an average margin of €65 per order, €15 per order is left after ad costs. If a promotion pushes the margin down to €45, every sale through ads costs €5 more than it brings in.
Where it goes wrong
CPA is often confused with CPL, but a lead is not yet a customer. In lead generation, calculate CPA per customer, including the leads that never convert.
Each ad platform also counts conversions using its own attribution. So do not compare the CPA in Google Ads and Meta one-to-one with your own revenue figures.
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