CPA (Cost per Acquisition)
CPA is the average amount you spend to get one completed conversion, such as a sale, a sign-up or a qualified lead, however you define it.
CPA (cost per acquisition, sometimes cost per action) is total spend divided by the number of conversions it produced. The exact conversion depends on what you define as one: a purchase, a free trial sign-up, a lead form, a demo booking. Unlike CPC or CPM, CPA ties spend to a real business outcome rather than to attention or a click.
CPA only makes sense next to the value of that conversion. A 50 dollar CPA is excellent for a 400 dollar product and a loss for a 20 dollar one, so compare it to average order value or customer lifetime value, not to a generic benchmark from another industry.
To lower CPA, work both ends: tighter targeting and stronger creative reduce wasted spend on people unlikely to convert, and a clearer offer or a smoother landing page raises the conversion rate on the traffic you already have. A rising CPA over time on unchanged targeting usually means the audience is saturated.
Examples
- Spending 3,000 dollars to generate 60 sign-ups gives a CPA of 50 dollars.
- A subscription app with a 40 dollar CPA and a 90 dollar first-year value per customer is profitable from day one; the same CPA against a 25 dollar one-time product is not.