Contribution margin is the money left from a sale after you subtract the variable costs of making and delivering it. It is what each order "contributes" toward ad spend, fixed costs and profit. For Meta advertisers, it is the margin that sets how much a customer can cost before ads lose money.
How to calculate contribution margin
Contribution margin per order = revenue − variable costs
Contribution margin (%) = (revenue − variable costs) ÷ revenue
Variable costs are the ones that rise and fall with each order. For an online store, count:
- The product itself (cost of goods sold)
- Shipping and packaging
- Payment processing fees
- A fair allowance for refunds and returns
Leave out ad spend and fixed costs such as rent, salaries and software. Ad spend is what the contribution margin has to pay for, so subtracting it first would count it twice when you use the margin to set a target.
Take an online apparel store selling a jacket for $80:
| Item | Amount |
|---|---|
| Price | $80.00 |
| Product cost | $28.00 |
| Shipping and packaging | $7.00 |
| Payment fees | $2.50 |
| Returns allowance | $4.50 |
| Variable costs | $42.00 |
| Contribution margin | $38.00 (47.5%) |
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Try for Free ($0 Trial)Contribution, gross and net margin
Gross margin subtracts only the product cost, so it is higher than contribution margin. Net margin subtracts everything, so it is lower. The three are compared in the profit margin entry. Contribution margin sits in the middle and is the one that suits ad decisions, because it has the same costs as the orders your ads win and nothing else.
What it tells you about ad performance
A contribution margin turns into two numbers you can read in Ads Manager.
- Break-even ROAS = 1 ÷ contribution margin (%). For the jacket store, 1 ÷ 0.475 is about 2.1. At a return on ad spend of 2.1, ad spend eats the whole $38 and the store breaks even on the order.
- Break-even cost per acquisition = contribution margin per order. The store can pay up to $38 for a customer's first purchase. Above that, each new customer costs money. See cost per acquisition (CPA).
The two agree: $80 ÷ $38 is about 2.1, so a ROAS of 2.1 at an $80 order value means a $38 CPA.
Anything past break-even is profit. At a ROAS of 3, ad spend per order is $80 ÷ 3, about $26.67, and $38 − $26.67 leaves $11.33 per order.
Common mistakes
- Using gross margin. It ignores shipping, fees and returns, so the break-even ROAS comes out too low and campaigns that lose money look fine.
- One margin for the whole catalog. Products differ. A campaign selling a high-margin item has a lower break-even ROAS than one selling a discounted line, so use the margin of what the campaign actually sells.
- Forgetting discounts. A sale price changes revenue per order, and the margin with it. Recalculate when you run a promotion.
- Counting fixed costs. Rent does not change with the next order, so it does not belong here.
Example. The jacket store raises its autumn sale to 25% off, so the price falls to $60 while costs stay at $42 (the returns allowance would likely change too, but keep it simple). Contribution drops to $18, or 30%, and break-even ROAS rises from 2.1 to 3.3. A campaign that was profitable at ROAS 2.5 now loses money.
In Madgicx. AI Marketer audits your Meta ad account and prepares budget and creative changes for you to approve, so you can hold campaigns to the break-even ROAS you set from your margin.
FAQ
What is the contribution margin formula?
Revenue minus variable costs gives the contribution margin per order. Divide that by revenue for the percentage. With an $80 jacket and $42 of variable costs, it is $38, or 47.5%.
What is the difference between contribution margin and gross margin?
Gross margin subtracts only the cost of the product. Contribution margin also subtracts shipping, payment fees and other per-order costs. Contribution margin is lower, and closer to what you actually keep from a sale.
How do I use contribution margin to find break-even ROAS?
Divide 1 by the margin as a decimal. A 47.5% margin gives 1 ÷ 0.475, or about 2.1. You can then use it as your ROAS target floor.
Is contribution margin before or after ad spend?
Before. It covers costs of the order itself. Ad spend is what you compare it with: the margin per order is the most you can spend on ads for that order before it loses money.
Does contribution margin include fixed costs?
No. Fixed costs such as rent and salaries do not change with each order. They are covered by what the orders contribute, which is why it has that name.
Related
- Related terms: Profit margin, Return on ad spend (ROAS), Average order value (AOV)
- Tool: Work out your break-even ROAS from your costs, a calculator that turns your prices and costs into the ROAS where ads stop losing money
