The Critical Distinction: True CPA vs. eCPA
Understanding the difference between calculated metrics and actual pricing
This is where many web3 advertisers get confused. Most advertising platforms will report a "CPA" value in their dashboards, but there's a crucial difference between true CPA pricing and effective CPA (eCPA).
This is a calculated metric based on what you've already spent and the results you achieved. If you spent $10,000 on CPM or CPC ads and got 100 conversions, your eCPA is $100. This is historical reporting, not pricing.
- You cannot determine your CPA value beforehand
- Your actual cost is unknown until after the campaign runs
- Risk remains entirely with you - if conversions drop, your eCPA goes up
- Most platforms report eCPA but charge CPM or CPC
In a true performance/CPA network, you agree on a fixed target cost per acquisition upfront, and only pay when that conversion happens; if the network can't deliver profitable conversions at that CPA, campaigns are usually stopped entirely, and you pay nothing when there are no conversions.
- You determine your acceptable CPA beforehand based on your unit economics
- Budget planning is more predictable — you know the unit cost per conversion upfront
- Risk shifts to the network — they are paid only when agreed conversions occur
- Requires sophisticated targeting and attribution models
The distinction matters enormously for budget planning and risk management. With eCPA reporting on CPM/CPC campaigns, you might plan for a $50 CPA but end up with a $200 eCPA if targeting or creative underperforms. With true CPA pricing, you set your $50 target and the network either delivers or you don't pay.