Why cpa matters
For most accounts it is the number the whole thing is judged on, because it maps directly onto whether the business makes money at a given volume.
What this looks like with real numbers
Spend $4,800 and get 96 conversions: a $50 CPA. But if 40 of those are add-to-carts counted as conversions because of how the event was configured, the real cost per purchase is $86. Name the event before you quote the number.
What it does not tell you
A CPA without a stated conversion event is meaningless. Cost per add-to-cart and cost per purchase are both 'CPA' and are not comparable. Always name the event.
The mistake people actually make
Comparing your CPA to a competitor's. Different event, different window and different margin structure make the comparison meaningless.
Questions, answered.
How do you calculate cpa?
Spend ÷ conversions. What one conversion cost you.
What goes wrong with cpa?
Comparing your CPA to a competitor's. Different event, different window and different margin structure make the comparison meaningless.
What does cpa not tell me?
A CPA without a stated conversion event is meaningless. Cost per add-to-cart and cost per purchase are both 'CPA' and are not comparable. Always name the event.
Change the creative, not the dashboard
What one conversion cost you.