Marketing Efficiency Ratio Calculator
The ratio attribution settings cannot game.
Marketing efficiency ratio
3.44×
2.17× on new customers alone
MER counts all revenue against all spend, including the repeat orders your advertising did not directly touch. That makes it flattering and honest at once — flattering because returning customers inflate it, honest because it is the only ratio that cannot be gamed by attribution settings. Watching the new-customer version alongside it separates growth from harvest.
How the Marketing Efficiency Ratio Calculator works
MER counts all revenue against all marketing spend, including repeat orders your advertising never touched. That makes it flattering and honest at once — flattering because returning customers inflate it, honest because no attribution setting can move it.
Not financial advice. Marketplace fees change, and they vary by country, plan and seller status. Every rate here is an editable default, not a quoted price — check the platform's current fee schedule before you price a product against it. This is not tax or business advice.
Frequently asked questions
What is marketing efficiency ratio?
Total revenue divided by total marketing spend. Unlike channel ROAS it uses figures from your own accounts, which is why it cannot be inflated by attribution windows.
How does MER differ from ROAS?
ROAS is per-channel and attribution-dependent; MER is business-wide and comes from your P&L. Summing channel-reported revenue routinely exceeds total sales, and MER is what exposes that.
What is new customer MER?
The same ratio using only revenue from first-time buyers. Watching both separates genuine growth from harvesting an existing base, which the blended figure conflates.
What MER should I target?
One divided by the share of revenue available for marketing after contribution margin, profit target and overheads. It is the same arithmetic as target ROAS, applied to the whole business.