Blended ROAS
Blended ROAS is total revenue divided by total ad spend across all channels. It's equivalent to MER, the honest top-down ad efficiency metric.
Blended ROAS = Total Revenue / Total Ad SpendWhat does Blended ROAS actually mean?
Blended ROAS is the same calculation as MER (Marketing Efficiency Ratio): total revenue divided by total ad spend. The two terms are interchangeable; ‘blended ROAS’ is more common in DTC, ‘MER’ in finance contexts.
The usefulness of blended ROAS is that it's observable from your finance system without trusting any platform's reported attribution. Meta, TikTok and Google each report their own attributed ROAS, and usually all three over-count because they overlap on the same conversions. Adding their reported numbers up gives a fictional total. Blended ROAS sidesteps the double-counting entirely.
Most mature DTC brands track both: platform ROAS for campaign optimization, blended ROAS for business health. The gap between them is a useful diagnostic: if reported ROAS is 4× and blended is 1.8×, you're double-counting roughly 50%.
Example
Meta reports 4× ROAS on $30K spend, TikTok reports 3× on $20K, Google reports 3.5× on $15K. Total reported revenue (with double-counting) = $250K. Actual revenue = $180K. Blended ROAS = $180K / $65K = 2.8×.
When it matters
Blended ROAS is the honest ad efficiency number. Platform-reported ROAS is for optimization; blended is for profit.
Related terms
MER
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.
ROAS
ROAS measures revenue generated for every dollar of ad spend. A 4× ROAS means $4 in revenue for each $1 spent.
Attribution
Attribution determines which ad touchpoint receives credit for a conversion, using last-click, first-click, time-decay or data-driven models.
ROI
ROI is profit (revenue minus cost) divided by cost. Unlike ROAS, ROI accounts for COGS, fulfillment and overhead.
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