Definition
CPA (cost per acquisition) is the average advertising cost to win one conversion, such as a sale, sign-up or lead: total ad spend divided by conversions.
CPA explained
CPA ties ad spending to outcomes. If a campaign spends a given amount and produces a certain number of leads, the CPA is the spend divided by the leads. It is often a more useful measure than CPC, because it combines the cost of clicks with how well your landing pages convert them.
In Google Ads, Target CPA is also a Smart Bidding strategy: you tell Google the average cost per conversion you want, and it sets bids in each auction to get as many conversions as possible at around that cost. It needs reliable conversion tracking and enough conversion data to work well.
Set CPA targets from your economics, not from industry averages. Work out what a customer is worth, what share of leads become customers, and therefore what you can afford to pay per lead. Then measure CPA by campaign, keyword and audience, because an account-wide average can hide campaigns that lose money.
Example
Your software brand knows a new customer is worth a certain amount over their first year and that one in five demo requests becomes a customer. That tells you the maximum you can pay per demo request, so you set a Target CPA below it and pause keywords that consistently exceed it.
Why it matters
CPA shows whether paid media is buying customers at a price the business can sustain.
Related service
Google Ads Management
Search, Shopping and Performance Max campaigns built around tracked conversions and cost per acquisition.
Google Ads management servicesWork it out with the Google Ads Budget & Break-even CPC Calculator
Sources
- Google Ads Help: About Smart Bidding (checked 30 Sep 2026)
Published by Vidern, founded and led by Malhar Shah. Updated .
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Related terms
- ROAS (Return on Ad Spend)ROAS (return on ad spend) is the revenue generated by advertising divided by the cost of that advertising, often written as a ratio or percentage.
- Smart BiddingSmart Bidding is a set of Google Ads bid strategies that use Google AI to set bids in each auction to maximize conversions or conversion value.
- Conversion trackingConversion tracking records valuable actions people take after seeing your ads or visiting your site, such as purchases, sign-ups, calls or leads.
- CPC (Cost Per Click)CPC (cost per click) is the amount an advertiser pays for each click on an ad, with average CPC being total cost divided by total clicks.
- Conversion rateConversion rate is the percentage of visitors or sessions that complete a goal, such as a purchase, sign-up or enquiry, out of all visitors or sessions.