CPA vs CAC (plain English)
CPA is the cost per conversion in a channel (purchase/lead/signup — you must define it). CAC is the overall cost to acquire a customer, usually blended across all channels and costs.
Shortcut: CPA = campaign-level. CAC = business-level.
Compute CPA from CPM, CTR and CVR
CPC = CPM ÷ (1000 × CTR)CPA = CPC ÷ CVR
Use: CPA Calculator.
Break-even CPA
Max CPA ≈ (AOV × (1 − refunds)) × (gross margin − fees)
FAQ
Is CPA the same as CAC?
No. CPA is usually channel cost per conversion; CAC is blended business cost per customer.
Include salaries in CAC?
For “true CAC”, include acquisition-related salaries/tools. For optimization, media CPA can still help.