CM3 MER: Contribution Margin Marketing Efficiency

CM3 MER measures contribution margin (after marketing) as a percentage of ad spend—how much profit your advertising generates after all variable costs.

Formula

CM3 MER = ( CM3 ÷ Total Ad Spend ) × 100

Formula Components

Metric	Definition
CM3 (Contribution Margin)	Profit after COGS, fulfillment, and marketing
Total Ad Spend	Combined advertising spend across platforms

Metadata
Type	Percentage
Data Source	Shopify, Meta Ads, Google Ads
Aggregation	Ratio

Example

Your Shopify store has $42,500 CM3 and spent $25,000 on advertising.

Component	Value	Calculation
CM3	$42,500	Contribution margin
Ad Spend	$25,000	Advertising cost
CM3 MER	170%	$42,500 ÷ $25,000 × 100

How It Works

CM3 MER shows contribution margin relative to ad spend. A 170% CM3 MER means your ads generate 1.7x their cost in contribution margin. This margin covers agency fees, OPEX, and other fixed costs.

When to Use

Scenario	Action
Measuring ad profitability	CM3 MER > 100% means positive contribution margin
Setting efficiency targets	Track CM3 MER against your fixed cost requirements
Campaign optimization	Focus spend on campaigns with highest CM3 MER
Profitability modeling	Use CM3 MER for break-even analysis

Metric	Relationship
CM3 ROAS	CM3 per ad dollar (same concept, different format)
CM2 MER	Variable margin as % of ad spend
CM4 MER	Operating profit as % of ad spend

See all Performance metrics →