What MER measures
MER, or marketing efficiency ratio, is total revenue divided by total marketing spend over the same period, across every channel at once. A brand that books 300,000 dollars of revenue in a month on 75,000 dollars of spend has an MER of 4. It ignores platform attribution entirely, which is why finance teams and DTC operators lean on it.
The confusable neighbour is ROAS, which divides the revenue one platform attributes to its own ads by the spend on that platform. ROAS answers which campaign the pixel credits; MER answers whether the business as a whole gets enough back for everything it spends. Some teams call MER blended ROAS, and both names describe one calculation.
How brands running UGC use it
Creator content complicates platform attribution. A strong TikTok video sends people who later search the brand on Google, buy on Amazon or return through an email, and none of those sales show up under the TikTok campaign. MER catches that spillover because it counts all revenue, so it works as the sanity check above in-platform numbers.
In practice a team sets a target MER from its margins, watches it weekly and treats platform ROAS as a steering signal inside that ceiling. When a new batch of UGC ads goes live and MER holds or rises while spend grows, the creative is probably pulling its weight even if one dashboard disagrees.
Worked example
Say a skincare brand spends 40,000 dollars on Meta and TikTok ads plus 8,000 on creator fees in March, and books 192,000 dollars of total revenue. Counting creator fees as marketing spend, MER is 192,000 divided by 48,000, which is 4.0. Leaving the fees out gives 4.8, a flattering number that hides what the content itself cost.
In April the brand doubles ad spend behind three winning creator videos. Revenue rises to 290,000 on 88,000 of total spend, an MER of about 3.3. Whether that is acceptable depends on contribution margin, so the target has to come from your own unit economics. The ROI calculator is a quick way to test those assumptions.
Common mistakes
Comparing MER across brands is the first trap. A subscription app and a furniture retailer carry completely different margins, so one ratio can mean profit for the first and a loss for the second. Set the floor from your own gross margin and CAC tolerance.
The second is changing the definition mid-quarter. Decide whether spend includes creator fees, agency retainers and tooling, write it down and keep it fixed, otherwise a month-on-month rise may only reflect a new formula. Remember too that MER lags: a creator video launched this week can still be selling next month.
How it's used
"MER held at 3.8 while we scaled the new creator batch, so the extra spend is paying for itself even though Meta under-reports it."
"Let's count creator fees inside MER from now on; leaving them out made Q2 look better than it was."