Free tool
MER calculator
Marketing efficiency ratio: total store revenue divided by total marketing spend, across every channel. No attribution model involved.
For the period you're measuring, not just ad-attributed revenue.
Meta, Google, and any other paid channel combined.
MER
6.25x
How this is calculated
MER is total revenue ÷ total marketing spend. Unlike ROAS, it doesn't rely on any platform crediting specific orders to specific ads, which makes it steadier but less useful for comparing individual campaigns. See MER vs ROAS for when to use which.