MER (Marketing Efficiency Ratio)
MetricMER is total company revenue divided by total marketing spend across all channels, measured as a holistic, attribution-free efficiency metric.
What is MER, in plain English?
Also called "Blended ROAS", MER is the high-level financial health check of your marketing. Instead of arguing over whether Google or Facebook deserves credit for a sale, MER takes all the money your company made in a month and divides it by all the money you spent on all ads combined.
How do you calculate MER?
MER = Total Company Revenue ÷ Total Marketing Spend
MER example
If your store made $100,000 in total sales this month and spent $20,000 across Google, Meta, TikTok, and influencer sponsorships combined, your MER is $100,000 ÷ $20,000 = 5.0 (or 5x).
Common MER mistakes
MER gives you the big picture, but it cannot tell you which specific campaign or creative is performing well or poorly. Use MER to set macro ad budgets and ensure overall business profitability, while using channel metrics underneath it for day-to-day tactical tweaks.
What is a good MER?
A good MER is one that keeps the whole business profitable after all marketing spend. Work it out from your contribution margin before marketing: if that is 50% of revenue, MER must exceed 2.0 just to break even on marketing. Track MER over time and against plan rather than against other brands, whose margins and channel mix differ.
MER FAQs
What is the difference between MER and ROAS?
ROAS divides the revenue an ad platform attributes to its own ads by that platform's spend. MER divides total business revenue by total marketing spend, with no attribution at all. MER can't be inflated by platforms double-claiming the same order, which is why many finance teams trust it.
How do you calculate MER?
Take total revenue for a period from your store or database — not from ad platforms — and divide it by total marketing spend across every channel in the same period. $100,000 of revenue on $25,000 of spend is an MER of 4.0.
When should I use MER instead of channel ROAS?
Use MER to set and defend the total marketing budget and to check that growth is profitable overall. Use channel ROAS or CPA underneath it for day-to-day campaign optimisation. If channel ROAS rises while MER falls, platforms are probably claiming sales that would have happened anyway.
Last reviewed October 3, 2026.