Marketing Efficiency Ratio is your total revenue over a period divided by your total marketing spend over the same period. It ignores attribution entirely — every euro of revenue counts whether it came from paid ads, organic, email, or word-of-mouth. Every euro of marketing spend counts regardless of channel.
MER = Total Revenue / Total Marketing Spend
Why it matters
After iOS 14.5 and the death of third-party cookies, last-click ROAS in Meta and Google undercounts true performance for most accounts. MER is the operator's escape hatch: it doesn't depend on any platform's pixel or modeled conversions. It's the macro signal — when you spend more, does revenue go up?
Typical ranges
- Healthy DTC ecommerce: 4× – 6× MER with paid + organic working together
- Brands heavily skewed to paid: 2.5× – 4× MER
- Mature brands with strong organic + retention: 6×+ MER
- MER below 2× often means paid is propping up a brand that organic / repeat isn't yet supporting
MER vs ROAS
ROAS is per-campaign and per-channel; MER is portfolio-wide. They're not in conflict — track both. Use ROAS to decide which campaign to scale; use MER to check that scaling actually moved the business and not just shifted credit between channels.