--- title: "Contribution Margin: Definition and Formula | MarginFix" description: "Contribution margin is revenue minus every variable cost of an order. Why it is the number marketing spend has to clear, and how an audit rebuilds it." url: https://marginfix.ai/glossary/contribution-margin/ lastmod: 2026-10-11 --- Your number See this page in your own figures: industry, spend and the estimated leak. [Run the estimator →](/estimator/) [Home](/) › [Glossary](/glossary/) › Contribution margin 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 Oct 2026 - 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. - /cases/bestsellers-were-priced-below-their-true-landed-cost/DTC / Ecommerce ### Bestsellers were priced below their true landed cost - +$59k a year, findings in 6 days. - Read the case → - /cases/scaling-spend-was-hiding-a-134k-annual-margin-leak/DTC / Ecommerce ### Scaling spend was hiding a $134k annual margin leak - +$134k a year, findings in 6 days. - Read the case → - /cases/free-shipping-was-quietly-deleting-the-margin-on-every-third/DTC / Ecommerce ### Free shipping was quietly deleting the margin on every third order - +$47k a year, findings in 5 days. - Read the case → - /cases/fba-fees-and-returns-had-overtaken-the-margin-on-the-hero-as/DTC / Ecommerce ### FBA fees and returns had overtaken the margin on the hero ASINs - +$61k a year, findings in 6 days. - Read the case → - /cases/configurator-upsells-were-discounted-below-their-cost/Manufacturing ### Configurator upsells were discounted below their cost - +$57k a year, findings in 6 days. - Read the case → - /cases/returns-processing-cost-was-missing-from-channel-economics/Retail ### Returns processing cost was missing from channel economics - −$69k a year, findings in 7 days. - Read the case → - /cases/dtc-ads-were-cannibalising-higher-margin-retail/Manufacturing ### DTC ads were cannibalizing higher margin retail - +$73k a year, findings in 7 days. - Read the case → - /cases/small-order-handling-cost-exceeded-the-margin-on-the-order/Manufacturing ### Small order handling cost exceeded the margin on the order - +$57k a year, findings in 6 days. - Read the case → 05 ## Terms and guides related to Contribution margin ### Related terms - [Blended ROAS](/glossary/blended-roas/) Return on ad spend measured across every channel at once. - [MER](/glossary/mer/) Total revenue divided by total marketing spend, a blended, platform independent efficiency measure. - [Margin leak](/glossary/margin-leak/) A recurring, usually invisible loss of marketing margin, whether wasted paid spend, mispriced offers or retention drop off, that a healthy looking blended metric conceals. - [Payback period](/glossary/payback-period/) The time for a customer's contribution margin to repay their acquisition cost. - [LTV:CAC](/glossary/ltv-cac/) Lifetime value to customer acquisition cost, a headline health metric that misleads when LTV is built on revenue instead of contribution margin. - [CAC](/glossary/cac/) The fully loaded cost to win one customer: acquisition spend divided by new customers. - [Take rate](/glossary/take-rate/) The percentage a marketplace keeps from each transaction. - [Dunning](/glossary/dunning/) The process of retrying failed recurring payments. - [Marketing and margin audit](/glossary/marketing-and-margin-audit/) An independent, evidenced review of marketing spend and unit economics that finds where budget leaks, quantifies the recoverable margin and hands over a prioritized fix list. ### Guides that use this term - [The five leak patterns](/margin-leaks/) Mispriced offers among the five, with how an audit tests the price. - [Where SMB marketing budgets leak](/insights/where-smb-marketing-budgets-leak/) Why the marketing can work and the margin still disappear. - [Your ROAS is lying to you](/insights/roas-attribution-field-guide/) Why a return on ad spend means nothing until it meets the margin. - [The benchmark](/benchmark/) Where 74 SMB marketing budgets leaked, by share of spend and by industry. - [DTC and ecommerce marketing audit](/industries/dtc-ecommerce/) Where ecommerce budgets leak, from landed cost to free shipping thresholds. - [Audit or consultant](/compare/marketing-audit-vs-consultant/) Cost, speed and what you walk away with, side by side. 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 →](/margin-leaks/) ## 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. [Book the audit](/book/) [Back to the glossary](/glossary/) Fixed fee. No retainer. NDA first. Go deeper ## Contribution margin and the wider audit evidence - [All 14 terms The full glossary: every term with a formula and a worked example.](/glossary/) - [All 74 findings Ranked by annual value, $58k median, each one a real case.](/findings/) - [The benchmark Where 74 SMB marketing budgets leaked, by share of spend and by industry.](/benchmark/) - [Margin leaks The five leak patterns in depth: what each one is and how an audit finds it.](/margin-leaks/) - [Marketing audit checklist Thirty checks across paid media, attribution, pricing, retention and reporting.](/marketing-audit-checklist/) - [What an audit costs The 2026 market ranges with sources, against the fixed fee tiers.](/marketing-audit-cost/)