MER / Blended ROAS

What is MER? MER (Marketing Efficiency Ratio, also called Blended ROAS) is total store revenue divided by total marketing spend across every channel. Unlike platform-specific ROAS, it captures the cross-channel reality — overall spend efficiency without arguing about attribution. It is the metric that tells you whether your entire marketing operation is working, not just individual channels. While platform-specific ROAS only measures revenue attributed to ads on that platform, MER captures everything: organic traffic, brand search, word of mouth, email, and all the revenue that platforms cannot or do not attribute.

MER has become the preferred north-star metric for sophisticated DTC brands because it accounts for the well-documented attribution gaps in post-iOS 14 tracking. When Meta reports a 4x ROAS but your store only grew 2x relative to spend, MER shows the real picture. It also reveals the true value of channels like email and organic social that drive revenue without showing up in platform attribution.

A healthy MER for most ecommerce brands falls between 3x and 5x. Brands with high margins (60%+) can operate profitably at lower MERs, while low-margin brands need higher efficiency. The organic revenue percentage input helps you understand how much of your total revenue is coming from non-paid sources — a critical indicator of brand strength and long-term sustainability. Brands overly dependent on paid channels (organic under 20%) face higher risk if ad costs rise or platform algorithms shift.

Track MER monthly alongside platform ROAS. When MER trends down while platform ROAS stays flat, it usually means your paid spend is cannibalizing organic revenue rather than creating incremental growth. When MER trends up, your brand is building momentum beyond what paid ads alone can explain.