Contribution margin

When you start in marketing, most of the numbers you see are about getting sales: clicks, conversion rates, cost per acquisition, ROAS. Contribution margin is about something different. It tells you what each sale actually leaves behind for the business.

Once you learn to think in contribution margin, you’ll find yourself asking better questions in every meeting. And you’ll be one of the few people in the room who can connect a campaign to the company’s bank balance.

▸ Definition — Contribution margin: the money a sale contributes towards the business’s fixed costs and profit, after taking away every cost that only exists because that sale happened.

The idea in one picture

Imagine a sale as a $100 note arriving in the business. Before it can pay for rent, salaries or software, some of it is handed straight back out:

1. To whoever made or supplied the product (cost of goods)
2. To the courier and the packaging supplier (fulfilment)
3. To the payment provider (transaction fees)
4. To the ad platform that found the customer (marketing cost per order)
5. To the customer, if they return it or used a discount

Whatever is left in your hand is that sale’s contribution. It “contributes” to paying for everything else.

▸ Example — One order, worked through. A customer buys a jacket for $80. Product cost $32. Delivery and packaging $7. Payment fee $2. Ad cost for this order $22. Average returns allowance $5. Contribution = $80 − $32 − $7 − $2 − $22 − $5 = $12, or 15% of the sale. Illustrative numbers.

Gross margin vs. contribution margin

These two are easy to mix up. The difference is how many costs you subtract.

The jump from 60% to 15% is the whole point. A product can look very profitable on gross margin and only just pay its way once delivery, fees, returns and advertising are in.

▸ Margin note — Variable costs rise and fall with each sale (product, delivery, fees, ads). Fixed costs stay the same whether you sell one jacket or a thousand (rent, salaries, software). Contribution margin only subtracts the variable ones.

Why marketers should care

ROAS tells you revenue per ad dollar. Contribution margin tells you whether that revenue was worth having. There are three situations where this changes decisions:

• Comparing channels. A marketplace might show a higher ROAS than your own website, but charge commission and fees that leave less contribution per order.
• Running discounts. A 20% discount doesn’t cut contribution by 20%. On the jacket above, $16 off wipes out more than the whole $12 contribution, so every discounted sale loses money.
• Choosing what to advertise. Two products with the same ROAS can leave very different contributions. Push the one that leaves more.

How to calculate it for your business

You don’t need a finance degree. Start with one product and an honest spreadsheet:

1. Take the average selling price after discounts.
2. Subtract the product cost (ask finance or operations, they will have it).
3. Subtract average delivery, packaging and payment fees per order.
4. Subtract a returns allowance (average return rate × cost of a return).
5. Subtract marketing cost per order (ad spend ÷ orders from ads).

The answer is your contribution per order. Do it for your three biggest products and you’ll know more about the business than most dashboards can tell you.

It’s normal to feel unsure about asking finance for cost numbers in your first job. Most finance teams are delighted when a marketer asks. It signals that you care about profit, not just activity.

Take it to work