Glossary /
MER
Efficiency & cost
MER
Your total revenue divided by your total ad spend — the blended, attribution-proof view of whether marketing as a whole is working.
Attribution & Measurement
Unit Economics
Data Governance & Nomenclature
Creative & Delivery
Audiences & Targeting
Mobile & Privacy
MER (Marketing Efficiency Ratio) is total business revenue divided by total ad spend across all channels. It's a blended efficiency number that ignores attribution entirely.
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What is MER?
MER, sometimes called blended ROAS, zooms all the way out. Instead of asking what each platform's ads returned, it asks whether your entire marketing investment is producing revenue for the business as a whole. Total revenue over total spend — no attribution, no windows, no platform claims. It matters because attribution is broken. iOS changes, cookie loss, and self-serving platform reporting mean channel-level ROAS is increasingly unreliable. MER sidesteps all of it by using numbers you can fully trust: actual revenue from your books and actual spend from your accounts. Ecommerce teams lean on MER as a north-star efficiency metric and a sanity check on inflated platform ROAS. The tradeoff is that MER tells you nothing about which channel drove what — it's a portfolio metric, useful for steering total spend, not for allocating it between platforms.
MER formula
MER = Total Revenue ÷ Total Ad Spend
Total Revenue is all revenue the business booked in the period, from every source — not just ad-attributed revenue. Total Ad Spend is everything you spent across all advertising channels combined. Divide total revenue by total spend for a single blended efficiency ratio.
Worked example
One month, whole business.
Total Revenue
$500,000
Total Ad Spend (all channels)
$100,000
MER
5.0x
$500,000 ÷ $100,000 = 5.0x
MER ignores attribution by design. It includes organic and repeat revenue no single platform can claim.
MER formula
MER = Total Revenue ÷ Total Ad Spend
Total Revenue is all revenue the business booked in the period, from every source — not just ad-attributed revenue. Total Ad Spend is everything you spent across all advertising channels combined. Divide total revenue by total spend for a single blended efficiency ratio.
Worked example
One month, whole business.
Total Revenue
$500,000
Total Ad Spend (all channels)
$100,000
MER
5.0x
$500,000 ÷ $100,000 = 5.0x
MER ignores attribution by design. It includes organic and repeat revenue no single platform can claim.
How MER differs across ad platforms
Total revenue (Shopify/your books)
The numerator comes from your source of truth for revenue — Shopify, your ecommerce platform, or finance system — counting all sales including organic, direct, and repeat. No ad platform supplies this number, which is exactly why MER is trusted.
Google Ads + Meta + TikTok spend (combined)
The denominator is total spend summed across every platform. Spend, unlike attributed revenue, is unambiguous and additive — each platform reports exactly what you paid it, so the sum is real and double-count-free.
No single platform
No ad platform reports MER, because no platform sees your total revenue or your competitors' spend. MER lives above the platforms by design — it can only be assembled by combining your business revenue with all-channel spend.
Common MER misconceptions
MER and ROAS measure the same thing.
ROAS uses ad-attributed revenue for a specific platform or campaign; MER uses total business revenue over total spend. MER is almost always higher because it includes organic and repeat sales no ad gets credit for.
A good MER tells you which channels to invest in.
MER is blended and channel-agnostic by design. It tells you if total spend is efficient, not where to shift budget — you still need channel-level signals and incrementality testing for allocation.
Frequently Asked Questions
What is MER in simple terms?
MER is your whole company's revenue divided by everything you spent on ads. A MER of 5 means the business made $5 of total revenue for every $1 of ad spend.
How is MER calculated?
Why does MER differ across ad platforms?
How does Clarisights report on MER?
Attribution & Measurement
Unit Economics
Data Governance & Nomenclature
Creative & Delivery
Audiences & Targeting
Mobile & Privacy
MER (Marketing Efficiency Ratio) is total business revenue divided by total ad spend across all channels. It's a blended efficiency number that ignores attribution entirely.
?
?
What is MER?
MER, sometimes called blended ROAS, zooms all the way out. Instead of asking what each platform's ads returned, it asks whether your entire marketing investment is producing revenue for the business as a whole. Total revenue over total spend — no attribution, no windows, no platform claims. It matters because attribution is broken. iOS changes, cookie loss, and self-serving platform reporting mean channel-level ROAS is increasingly unreliable. MER sidesteps all of it by using numbers you can fully trust: actual revenue from your books and actual spend from your accounts. Ecommerce teams lean on MER as a north-star efficiency metric and a sanity check on inflated platform ROAS. The tradeoff is that MER tells you nothing about which channel drove what — it's a portfolio metric, useful for steering total spend, not for allocating it between platforms.
MER formula
MER = Total Revenue ÷ Total Ad Spend
Total Revenue is all revenue the business booked in the period, from every source — not just ad-attributed revenue. Total Ad Spend is everything you spent across all advertising channels combined. Divide total revenue by total spend for a single blended efficiency ratio.
Worked example
One month, whole business.
Total Revenue
$500,000
Total Ad Spend (all channels)
$100,000
MER
5.0x
$500,000 ÷ $100,000 = 5.0x
MER ignores attribution by design. It includes organic and repeat revenue no single platform can claim.
How MER differs across ad platforms
Total revenue (Shopify/your books)
The numerator comes from your source of truth for revenue — Shopify, your ecommerce platform, or finance system — counting all sales including organic, direct, and repeat. No ad platform supplies this number, which is exactly why MER is trusted.
Google Ads + Meta + TikTok spend (combined)
The denominator is total spend summed across every platform. Spend, unlike attributed revenue, is unambiguous and additive — each platform reports exactly what you paid it, so the sum is real and double-count-free.
No single platform
No ad platform reports MER, because no platform sees your total revenue or your competitors' spend. MER lives above the platforms by design — it can only be assembled by combining your business revenue with all-channel spend.
Common MER misconceptions
MER and ROAS measure the same thing.
ROAS uses ad-attributed revenue for a specific platform or campaign; MER uses total business revenue over total spend. MER is almost always higher because it includes organic and repeat sales no ad gets credit for.
A good MER tells you which channels to invest in.
MER is blended and channel-agnostic by design. It tells you if total spend is efficient, not where to shift budget — you still need channel-level signals and incrementality testing for allocation.
Related Terms
Frequently Asked Questions
What is MER in simple terms?
MER is your whole company's revenue divided by everything you spent on ads. A MER of 5 means the business made $5 of total revenue for every $1 of ad spend.
How is MER calculated?
Why does MER differ across ad platforms?
How does Clarisights report on MER?
See Viewable Impression across every channel in one report
See Viewable Impression across every channel in one report
See viewability and vCPM across every platform—display, video, programmatic— in one normalized report, instead of reconciling vendor numbers by hand.
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