MER Calculator
MER, or marketing efficiency ratio, is total revenue divided by total ad spend across every channel. It is the vocabulary of sophisticated DTC operators because it sidesteps the attribution wars: instead of asking which channel gets credit for a sale, it asks whether the whole marketing engine is producing revenue efficiently. This free MER calculator returns your ratio and your ad spend as a share of revenue in one step, and it requires no email.
Enter your numbers to see results.
Showing the inverse alongside the ratio is intentional. MER as a multiple tells you revenue per dollar of spend; ad spend as a percentage of revenue (sometimes called aMER) is the same relationship in the language finance teams use to set budgets. Both come straight from total revenue and total spend.
Use it to track blended efficiency over time, set a spend ceiling as a share of revenue, or judge marketing health when platform-reported numbers no longer add up.
How it works
MER equals total revenue divided by total ad spend across all channels. Unlike campaign ROAS, it makes no attribution claims; it simply measures how much revenue the business produced for every dollar of marketing invested.
The inverse, ad spend divided by total revenue and multiplied by 100, expresses the same efficiency as a percentage of revenue. A MER of 4.0x is the same as spending 25% of revenue on advertising.
Worked example
Suppose a brand generates $120,000 in total revenue against $30,000 in total ad spend across all channels. MER is 120,000 divided by 30,000, or 4.0x.
Stated the other way, ad spend is 30,000 divided by 120,000, or 25% of revenue. Every dollar of marketing produced four dollars of total revenue.
What is a good MER?
A good MER depends on margin and growth stage, not on a universal target. Established, profit-focused brands often want a higher MER, frequently 4x or more, because they are optimizing for contribution. Growth-stage brands deliberately tolerate a lower MER, sometimes 2x or below, because they are buying market share and trust that lifetime value will repay the investment. Neither is wrong; they reflect different mandates.
Tie MER back to your margin. A brand with 60 to 80% gross margin can sustain a lower MER than a thin-margin business, because more of each revenue dollar survives to cover the spend. The honest question is whether your MER leaves enough contribution after product and operating costs, not whether it clears some benchmark number.
MER rose to prominence because attribution degraded. After iOS privacy changes broke deterministic tracking, platform-reported ROAS became unreliable and often double-counted conversions across channels. MER is harder to game because it uses total revenue and total spend, the numbers in your financials. Use campaign ROAS to optimize within a channel and MER to judge the whole engine, and compare your ratio to QRY's monthly paid media benchmarks for context.
See QRY's monthly paid media benchmarks to compare your numbers against the portfolio.
Frequently asked questions
What is a good MER?
A good MER depends on margin and growth stage. Profit-focused brands often target 4x or higher, while growth-stage brands accept 2x or lower to buy market share. The right number is the one that leaves enough contribution after product and operating costs, not a universal benchmark.
How do you calculate MER?
MER equals total revenue divided by total ad spend across all channels. For example, $120,000 in revenue against $30,000 in spend is a 4.0x MER. The inverse, ad spend as a share of revenue, would be 25%.
What is the difference between MER and ROAS?
ROAS is usually a channel-level number that credits revenue to a specific campaign, which depends on attribution. MER is total revenue divided by total ad spend across all channels, a blended view that makes no attribution claims. MER is harder to inflate and better for judging overall marketing health.
Why did brands shift to MER after iOS14?
Apple's privacy changes broke deterministic tracking, so platform-reported ROAS became unreliable and often double-counted conversions across channels. MER uses total revenue and total spend, the numbers that appear in financial statements, so it is far harder to game and gave operators a trustworthy efficiency measure when attribution degraded.
What is aMER or ad spend as a percentage of revenue?
aMER, sometimes called inverse MER, expresses marketing efficiency as ad spend divided by total revenue. A 4.0x MER is the same as spending 25% of revenue on advertising. Finance teams often prefer this framing because it sets a budget ceiling directly as a share of revenue.
Related calculators
Is your MER efficient for your stage?
See how your blended efficiency compares to QRY's managed portfolio with our monthly paid media benchmarks.
See the benchmarks