What is contribution margin?
Contribution margin is what a single order leaves behind after every variable cost, the costs that scale with each sale. Product, shipping, payment processing, and any other per-order expense come out. Ads and fixed costs do not.
Margin rate = Contribution margin ÷ Price
That leftover pool is the money each order gives you to buy traffic and cover overhead. It is the number that decides whether paid acquisition can ever work for your product. Two brands can run identical ads at identical CPAs, and a 60% margin rate scales while a 30% rate bleeds.
Worked example
Start from the prefilled numbers: price $80, landed product cost $22, shipping and fulfillment $8, plus 2.9% + $0.30 processing, which comes to $2.62 on an $80 order. Inserts and disputes add $2 of other variable costs.
$45.38 ÷ $80 = 56.7% margin rate
Each order keeps $45.38, a 56.7% contribution margin. Run 100 orders and you have banked $4,538 to pay for ads, overhead, and profit. The other 43.3% is spoken for: 27.5% product cost, 10% shipping, 3.3% processing, and 2.5% other variable costs.
What counts as a variable cost?
The test for every line item: does this cost exist because this specific order happened? If yes, it is variable and belongs in the calculator. If it shows up whether you ship 10 orders or 1,000, it is fixed and stays out.
Product cost (COGS): what it costs to put the order in a box, landed: units, freight in, duties. Blend it across a typical order; a best-case SKU number flatters the margin.
Shipping & fulfillment: the label on the box, what your 3PL bills to pick and pack it, and the mailer and filler it ships in. Count customer-paid shipping once; the FAQ covers how.
Payment processing: whatever your processor takes across all payment methods, averaged. The calculator prefills 2.9% + $0.30, the standard card rate, but installment plans and wallets carry their own fee schedules.
Other variable costs: the stragglers riding along with each order: a gift-with-purchase, an insert card, the refund and chargeback dollars an average order burns, support billed per ticket. Borderline calls follow the same test: a warehouse lease is fixed, but per-unit 3PL storage fees are variable.
Contribution margin vs. gross margin
Gross margin is price minus COGS, full stop. On the example order that is $80 − $22 = $58, a flattering 72.5%. Contribution margin also subtracts fulfillment, processing, and other per-order costs, landing at $45.38 and 56.7%. That 15.8-point gap, $12.62 per order, is real money gross margin pretends not to see.
The distinction matters because ad decisions run on contribution numbers. Bid against gross margin and you will happily pay $50 to acquire an order that only carries $45.38. Use gross margin for supplier negotiations and category comparisons; use contribution margin for anything that touches ad spend.
What margin does paid acquisition need?
Paid social stacks a large, volatile cost on top of your variable costs. As a directional rule, DTC brands that scale profitably on Meta or TikTok tend to run contribution margins around 55% or higher. Below roughly 40%, ordinary CPM and conversion-rate swings are enough to flip the whole account from profit to loss.
Your margin is also your break-even CPA. They are literally the same number. At $45.38 of contribution, $45.38 is the most you can pay to acquire an order before it loses money. Divide price by margin and you get break-even ROAS: $80 ÷ $45.38 = 1.76. The Break-Even ROAS Calculator runs that math and shows profit per order at common ROAS targets.
Frequently asked questions
What is the difference between contribution margin and gross margin?
Gross margin subtracts only COGS from price. Contribution margin subtracts every variable cost: COGS plus shipping, fulfillment, payment processing, and other per-order expenses. On the $80 example order the difference is $12.62. Gross margin flatters; contribution margin is the number your ad account actually spends against.
Should ad spend be included in contribution margin?
No. Contribution margin is what an order leaves behind before ads; it is the budget ads get to spend. Subtract your CPA from it and you get profit per order. Folding ad spend in makes the metric circular, because you need the margin first to know what CPA you can afford.
What about fixed costs like salaries, rent, and software?
Leave them out. Rent costs the same whether order 1,001 ships or not, so it has no business in a per-order metric. Fixed costs answer a different question: how many margin-positive orders per month it takes to clear overhead. Fold them into the margin and your target gets harsher the more you sell, which is backwards for a number meant to guide growth.
What contribution margin do I need for paid social?
Directionally, 55% or higher gives you room to pay auction prices and still bank profit. Between roughly 40% and 55%, paid social can work with a strong AOV or repeat purchase behind it. Below 40%, most accounts are one CPM spike away from losing money. These are directional ranges, not laws. Your break-even CPA is the real gate.
Should I raise prices or cut costs first?
Price usually moves faster. A $5 price increase adds about $4.85 of margin on this example order (processing takes its 2.9% cut), and it lands the day you change it. Cutting $5 of COGS takes a negotiation cycle. Test the price first: model what bundles and thresholds do to order value with the AOV Calculator, then chase landed costs, which compound quietly forever.
Does shipping I charge the customer count?
Yes, but only once. Either add shipping revenue to the price and keep the full shipping cost in its line, or net the two against each other. Free-shipping brands carry the whole cost in the shipping line. Both approaches give the same margin; double-counting is the only way to get it wrong.
Where StefanBrain fits
Contribution margin tells you what you can pay for a customer; actually acquiring customers under that number comes down to creative. StefanBrain works that side of the equation. It produces copy variants, landing pages, and ad creative in both static and video, then launches the strongest on Meta and steers the next round from live results. Once the margin is set, check how long each customer takes to earn back their acquisition cost with the CAC Payback Calculator.