MER (Marketing Efficiency Ratio) Calculator
Blended ROAS across every channel, total revenue ÷ total marketing spend. The metric iOS 14.5 made essential.
About this tool
Platform-reported ROAS over-counts because every channel claims the same conversion. MER (also called blended ROAS) divides your total store revenue by total marketing spend, giving you a single honest number that tracks holistic efficiency over time.
Why MER matters more post-iOS 14.5
iOS 14.5 broke deterministic attribution. Meta and TikTok now report modeled conversions that consistently overstate platform ROAS by 20–80%. MER bypasses the platform attribution layer entirely by dividing total store revenue (from Shopify) by total marketing spend. It's the only number that can't be inflated by attribution overlap.
MER benchmarks
- • Break-even MER: 1 ÷ gross margin (45% margin → 2.22x).
- • Healthy D2C: 3x–5x.
- • Top-quartile: 5x+.
- • nMER (new-customer MER): a tighter benchmark that strips repeat revenue from the numerator. Better for ranking acquisition channels.
Frequently asked questions
What is MER (Marketing Efficiency Ratio)? +
MER is total store revenue divided by total marketing spend, also called blended ROAS or true ROAS. Unlike platform-reported ROAS, MER can't be inflated by attribution overlap because both numbers come from your bank account, not from Meta or Google.
Why is MER more reliable than platform ROAS post-iOS 14.5? +
iOS 14.5 broke deterministic attribution. Meta and TikTok now report modeled conversions that overstate platform ROAS by 20-80%. Since multiple platforms claim the same conversion, summing their reported revenue double- or triple-counts. MER ignores all of that.
What's a healthy MER? +
Break-even MER is 1/gross margin. At 45% margin, break-even is 2.22x. Healthy D2C MER is 3-5x; top-quartile is 5x+. Track MER monthly, it's noisy week-to-week but trends cleanly over time.
Should I include organic revenue in MER? +
Yes, that's the point. MER is total revenue ÷ total marketing spend, including the organic and direct revenue your brand drives. If your MER is high because brand is strong, that's a real signal, not a flaw.
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