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Glossary · Unit economics

Contribution margin

Revenue minus every variable cost per order or unit: cost of goods, shipping, payment fees, returns. It is the real profit a marketing dollar defends, and the number blended ROAS quietly ignores.

  • Reviewed
  • 3 min read
  • Part of the 14 term glossary
  • Median finding $58k a year across 74 audits
01

What Contribution margin means

Contribution margin is what an order or a unit leaves behind after every variable cost it caused: the cost of the goods, shipping and packaging, payment fees, returns and the handling they need, marketplace and platform fees. It is what remains to pay for marketing, fixed costs and profit, and it is the number a marketing dollar is actually defending.

It is not gross margin. Gross margin usually stops at the cost of goods, so it leaves out the costs that grow with every order: the carrier, the payment processor, the returns desk. For a business that ships physical products or pays a fee on every transaction those costs are large, and a product with a healthy gross margin can contribute almost nothing once they are counted.

02

The Contribution margin formula and a worked example

The formula and an illustration; the corpus line is the audited figure behind it.

Contribution margin = revenue − variable costs

Worked example Illustration, not a client figure

A $100 order with $42 of goods, $9 of shipping, $3 of payment fees and $6 of returns allowance contributes $40. A 2.5× ROAS on that order spent $40 to win it, so the sale earned nothing.

03

Why Contribution margin matters in an audit

Contribution margin is the yardstick the audit measures marketing against, because a return on ad spend means nothing until it is set beside it. A 2.5× ROAS on an order that contributes 40% of its revenue spends exactly what the order earns; the sale grew revenue and added no margin. The break even ROAS is one divided by the contribution margin rate, and any campaign below it loses money on every order it wins.

The audit rebuilds contribution margin per order and per product from the ledger, the carrier invoices, the payment processor statements and the returns log, rather than from a standard cost set years ago. Freight, packaging, fees and return rates drift, prices often do not, and the leak is the gap that opens between them. In the published cases it shows up as bestsellers priced below their landed cost, free shipping thresholds that no longer match the basket, and upsells given away below what they cost to fit.

Mispriced offers made up 9% of audited SMB marketing spend and appeared in 47% of the 74 audits. Most of them are contribution margin findings: the marketing worked, and the order it won was not worth winning at that price.

04

Contribution margin in the audited cases

Published cases where Contribution margin was at the center of the finding, each with the audited annual figure.

06

Questions about Contribution margin

What is contribution margin?

Contribution margin is revenue minus every variable cost of the order: goods, shipping, packaging, payment fees, returns and platform fees. It is what each order leaves to pay for marketing, fixed costs and profit.

How do you calculate contribution margin?

Take the order value and subtract each variable cost it caused. A $100 order with $42 of goods, $9 of shipping, $3 of payment fees and $6 of returns allowance contributes $40, a 40% contribution margin. Do it per product and per channel, because the costs differ.

What is the difference between contribution margin and gross margin?

Gross margin usually subtracts only the cost of goods. Contribution margin also subtracts the costs that grow with each order, such as shipping, payment fees and returns, so it is lower and closer to what the order really earns. Marketing decisions belong on contribution margin. Read the five leak patterns →

Know the term. Now measure it in your own numbers.

Contribution margin, measured against your own accounts in 5 to 7 working days. $10k to $50k of findings, or your money back.

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Fixed fee. No retainer. NDA first.

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Contribution margin and the wider audit evidence