Gross Margin vs Contribution Margin: The Number That Actually Decides If You Grow

Gross margin is revenue minus the cost of the goods you sold. Contribution margin is revenue minus every variable cost of that sale – goods, shipping, payment fees, returns, fulfilment labour and platform commission. For a typical DTC brand the gap between the two is 15 to 25 percentage points, and every acquisition decision lives inside that gap.

The two definitions, side by side

Gross margin % = (Net revenue − COGS) ÷ Net revenue Contribution margin % = (Net revenue − COGS − all other variable costs) ÷ Net revenue

The lines that sit between them are the ones brands forget:

• Inbound freight, duty and clearance – part of landed cost, not overhead
• Outbound shipping and packaging, net of what the customer pays
• Payment processing and BNPL fees
• Marketplace or platform commission
• Pick, pack and per-order fulfilment charges
• The full cost of returns: refunded revenue, return shipping, inspection, write-off

Why the distinction changes decisions

Paid acquisition is funded out of contribution margin, never gross margin. A brand at 68% gross margin and 44% contribution margin has £44 per £100 of revenue to spend on customer acquisition, overhead and profit – not £68. Brands that budget from gross margin overspend on ads by exactly the size of that gap and then wonder why a "profitable" P&L drains cash.

Rough thresholds we use when reviewing a brand:

• Contribution margin under 25% – paid acquisition rarely works; fix price, landed cost or shipping first
• 25–40% – growth is possible on repeat purchase and disciplined creative, not on first-order economics
• Above 40% – you can genuinely buy customers, provided returns and discounting stay in check

Build it once, per SKU

Contribution margin at company level hides the story. Build it per SKU on a single row: net selling price after discounts, landed cost, shipping, fees, returns provision, and the resulting contribution in currency and in percent. Sort ascending. The bottom of that list is usually where the cash is going.

Then check two things monthly. First, the weighted average contribution margin – a shift of two points changes what you can afford to pay for a customer. Second, the spread: if half your contribution comes from three SKUs, your growth plan is really a plan for those three.

The one-line test

If someone asks what your margin is and the answer is a gross margin, you cannot yet tell whether growth makes you money. Contribution margin is the number the whole plan is built on – price, ad budget, discount policy and the point at which scale finally pays for the overhead.