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Three margins, not one. CM1 asks whether the product pays, CM2 whether the order pays, and CM3 whether the customer pays. A single contribution margin cannot tell you which of the three went wrong.
CM1after product costs
62,0%
€37.200,00 a month
CM2after shipping and fees
52,6%
€31.541,60 a month
CM3after ad spend
27,6%
€16.541,60 a month
EBITDAafter running costs
15,9%
€9.541,60 a month
What comes in
That is about 706 orders a month.
What goes out
↑ ↓ to nudge, Shift for ten. Commas or dots both work.
Each ad euro has to bring in €1,90 of net revenue to pay for itself. Yours brings in €4,00, so the ads pay their way.
You keep €15,90 of every €100 that comes in, across roughly 706 orders. Your heaviest single cost is cost of goods, at 38,0% of net revenue. Every share on this statement is measured against net revenue, which is what makes them comparable to each other.
An estimate from flat rates. In nouz every order is priced from the costs of its own day.
A contribution margin calculator takes net revenue and removes each cost layer in turn: goods for CM1, logistics and payment fees for CM2, advertising for CM3, overhead for EBITDA. Each margin appears in euros and as a share of net revenue, laid out exactly like a 34-line P&L.
Why three
Take two products with the same contribution margin of 22%. One is a heavy €40 item with a good purchase price and an expensive parcel. The other is a light €140 item with a poor purchase price and a cheap parcel. They look identical on a single figure and they need opposite decisions.
Splitting the margin into three layers makes the difference visible on sight. The heavy item has a strong CM1 and a weak CM2, so the answer is a better rate card or a smaller box. The expensive item has a weak CM1 that no amount of logistics work will fix, so the answer is a supplier conversation or a price rise.
The third layer is the one most stores never compute. CM3 takes advertising out, and it is where a product with a healthy CM2 turns out to be losing money because it takes €30 of ads to sell one. That is not a marketing problem or a product problem on its own; it is only visible when the two sit on the same statement.
Overhead comes off below all three and is deliberately not a contribution margin, because rent does not change when you ship one more parcel. What is left after it is EBITDA.
Where it goes wrong
Contribution margin is only useful if every cost is on the layer it belongs to. These four move around the most, and each one flatters a different margin.
The European mistake. Shopify shows a figure that includes VAT and, depending on where you look, includes orders that were later refunded. Neither is margin. Net revenue is what is left after returns and after tax, and it is the only denominator that makes the percentages comparable.
Get this wrong and all three margins are overstated by roughly a sixth at German rates, in the same direction, so nothing looks obviously broken.
What the customer paid for delivery is revenue and belongs at the top. What the carrier charged is a cost and belongs in CM2. Netting the two against each other hides both, and it is how a store ends up believing shipping is free when it is running a €2 loss on every parcel.
A gateway charges a percentage of the gross amount it moved, VAT and shipping included, plus a fixed fee per transaction. Applying the advertised percentage to net revenue understates the cost, and ignoring the fixed leg understates it badly on a low basket.
Use the blended rate you actually pay across every gateway, which is rarely the number on any one of their pricing pages.
Agency retainers, software subscriptions and salaries feel like marketing costs when they sit on a marketing budget, but they do not vary with the sale, so they belong below CM3. Only spend that bought this month’s orders belongs in the marketing line.
The exception worth knowing: an influencer retainer or a campaign booked as a one-off really is marketing, and nouz routes costs categorised as marketing into the marketing line rather than into overhead, so each euro is counted exactly once.
Worked example
The calculator’s own defaults, not a customer’s books. €60.000 of net revenue in a month across about 706 orders. Goods at 38%, a parcel at €6,40, gateways at 1,9%, €15.000 of advertising and €7.000 of fixed costs.
CM1 is 62,0%, which is a perfectly respectable apparel margin and the number most merchants would quote if asked. CM2 is 52,6%: shipping, packing and the payment fees took 9,4 points between them. CM3 is 27,6%, because 25,0% of net revenue went on advertising.
A store with a 62% margin kept 15,9% of what came in. Nothing here is dysfunctional and no single line is a scandal; the gap is just the sum of four ordinary costs that a gross-margin figure never shows.
Which is the point of computing three margins rather than one. If this store wanted another five points, the statement says exactly where to look first: advertising is the largest single cost below the goods, and it is the one that can be changed this week.
In the app
A calculator works from flat rates you type once. nouz prices every single order from the cost rules that were in force on that order's own date, and rebuilds the same statement every night from your own orders and your own ad spend.
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The long version
Want the long version rather than the arithmetic?
CM1 · CM2 · CM360,8% · 48,9% · 23,5%the same revenue, three margins10 min readCM1, CM2 and CM3 explained: the three margins ecommerce operators steer onCM1, CM2 and CM3 are contribution margins after product, fulfilment and marketing costs. What each level includes, the formulas, and a worked example.CM1, CM2 and CM3 explainednouz computes CM1, CM2 and CM3 for the store, for each period and for every product you sell, from your own orders and your own cost rules.