MERMarketing Efficiency Ratio
MER is total revenue divided by total ad spend. It's a blended, top-down profitability metric that's harder to game than platform ROAS.
MER = Total Revenue / Total Ad SpendWhat does MER actually mean?
Marketing Efficiency Ratio (MER), sometimes called ‘blended ROAS’, is total revenue divided by total ad spend, period. It ignores attribution windows, click vs view-through, and platform-reported conversions. It just asks: for every dollar spent on ads, how many revenue dollars did the business produce?
MER became the favored DTC metric circa 2022 after iOS 14 broke last-click attribution. Where platform-reported ROAS depends on which clicks the platform sees, MER is observable from the income statement. A brand with 4× platform ROAS but only 2× MER is over-counting somewhere.
Target MER depends on contribution margin. A 60%-margin DTC brand can profitably run a 1.5× MER (each $1 in ad spend produces $1.50 in revenue, $0.90 of which is contribution margin). A 25%-margin commodity needs 4×+ MER to break even.
Example
A DTC brand did $250K revenue last month with $80K total ad spend across all platforms. MER = $250K / $80K = 3.1×.
When it matters
MER is the metric finance teams trust. Use it to calibrate platform-reported ROAS, which is consistently inflated.
Related terms
ROAS
ROAS measures revenue generated for every dollar of ad spend. A 4× ROAS means $4 in revenue for each $1 spent.
ROI
ROI is profit (revenue minus cost) divided by cost. Unlike ROAS, ROI accounts for COGS, fulfillment and overhead.
TACoS
TACoS is total Amazon ad spend divided by total Amazon sales (organic + paid). It measures ad efficiency across all sales, organic included.
Attribution
Attribution determines which ad touchpoint receives credit for a conversion, using last-click, first-click, time-decay or data-driven models.
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