Cost per engagement (CPE)
Cost per engagement shows what a single interaction such as a like or comment cost on average.
CPE suits campaigns aimed at attention and conversation with the community. It doesn't show whether the interactions are genuine or lead to purchases. Bought likes and giveaways can lower it artificially.
Calculation
Example: A collaboration costs €2,000 and gets 8,000 likes and comments. The CPE is €2,000 ÷ 8,000 = €0.25.