Gross Margin

What Gross Margin means in practice

Gross margin determines how much of each pound of revenue is available to fund everything else — product development, acquisition, support and eventually profit. It is the structural reason software and services businesses can behave so differently at identical revenue.

What counts as a direct cost varies by model, and getting it right matters. For SaaS it is hosting, third-party APIs, payment processing and the support directly attributable to serving customers. For ecommerce it is cost of goods, fulfilment, shipping and returns. Excluding awkward costs like returns or support inflates margin and makes the model look healthier than it is.

Margin also constrains what growth strategy is viable. A business at 80% margin can spend heavily on acquisition and still recover it; one at 20% must acquire cheaply or rely on repeat purchases, because there is far less headroom per sale to pay for the customer.

How it is calculated

Worked example

Comparing a SaaS product and an ecommerce store, both at £100,000 monthly revenue.

• SaaS: hosting, APIs and processing total £18,000 → gross margin 82% (£82,000 available).
• Ecommerce: goods, shipping and returns total £72,000 → gross margin 28% (£28,000 available).
• Identical revenue, nearly three times the difference in money available to run the business.

Takeaway: The SaaS business can fund far more acquisition and product work from the same top line, which is why margin matters more than revenue when judging a model.

Common mistakes

• Excluding support, returns or payment processing to make margin look stronger.
• Confusing gross margin with net margin, which also deducts overheads.
• Comparing margin across business models where direct costs mean different things.
• Ignoring how margin erodes as customer support scales with volume.

Related tool: Break-even calculator.

Related terms

• Unit Economics — Unit economics are the direct revenues and costs associated with a single unit of your business — usually one customer — showing whether each one is profitable before overheads.
• Customer Lifetime Value — Customer lifetime value (LTV) is the total gross profit you expect to earn from a single customer across the whole of their relationship with you, before the cost of acquiring them.
• Break-Even Point — The break-even point is the level of sales at which total revenue exactly covers total costs, producing neither profit nor loss — the threshold a business must clear to become self-sustaining.
• Burn Rate — Burn rate is the speed at which a company spends its cash reserves, usually expressed per month. Net burn is spending minus revenue; gross burn is total spending regardless of income.