What is CPA? (Cost Per Acquisition (or Action))
CPA is the average cost to acquire one conversion — a sale, signup, or lead. When the action is a lead, it is often called CPL (cost per lead).
Formula
CPA = Ad Spend ÷ Conversions
Example
Spend $1,000 and get 20 conversions → CPA = $50 per conversion.
Why CPA matters
CPA ties spend directly to outcomes, making it the metric most closely tied to profitability. Keep CPA below your customer's value (or margin) to stay profitable.
What's a good CPA?
A healthy CPA is any figure comfortably below the profit a conversion generates.
Compare across every vertical: average cost per lead by industry →
Do the math: CPA calculator →