What is Contribution Margin?
What remains from a sale after every variable cost of fulfilling it, available to cover fixed costs and profit.
Contribution Margin = Selling Price - (COGS + Shipping + Packaging + Gateway Fees + Returns Provision)
A worked example
A jar of pickle sells for Rs 400. Cost of goods is Rs 150, shipping Rs 60, packaging Rs 20, payment gateway Rs 8, and a returns provision of Rs 32 at an eight per cent failure rate. Contribution margin is Rs 130, or 32.5 per cent, which sets your break-even ROAS at roughly 3.1.
Why it matters
Contribution margin is the number every other number depends on, and it is the one most brands have never calculated precisely. Break-even ROAS comes from it. Your maximum affordable CAC comes from it. Whether a discount is survivable comes from it. Set it wrong and every downstream decision inherits the error.
Gross margin is not a substitute, and confusing the two is where the trouble usually starts. Gross margin subtracts cost of goods and stops. Contribution margin keeps going through shipping, packaging, payment charges, marketplace commission and the cost of orders that fail. A brand quoting sixty per cent gross margin can easily be running at twenty-five per cent contribution margin once fulfilment is honest.
The gap between those two figures is exactly the gap between a business that looks profitable in a spreadsheet and one that runs out of cash.
The nuance most people miss
Returns belong in the calculation as a provision on every order, not as a separate line reviewed at year end. If fifteen per cent of your cash-on-delivery orders come back, then every COD order should carry a share of that cost, because you cannot know in advance which one will fail. Brands that treat returns as an exception rather than a variable cost consistently overstate margin, and the overstatement is largest exactly where volume is highest.
Common mistakes
- Using gross margin as though it were contribution margin, which overstates by a wide margin
- Leaving return-to-origin out of the calculation entirely
- Ignoring payment gateway charges and marketplace commission because they feel small individually
- Calculating once at launch and never revisiting it as costs and shipping rates change