Contribution margin calculator
What each order really leaves you, and how much of that you can spend winning the customer.
≈ 3 minutes
Work out my contribution margin
Which sales channel leaves you most
The channel that bills most is not always the one that leaves most. A marketplace with high prices can end up behind your own store once you deduct its fee, its fulfillment and its returns provision. This calculator pits the same product across up to four channels and tells you which one genuinely wins.
Every calculation runs in your browser. The figures you type are never sent to a server and are never stored.
Your results will appear here
Enter the product cost and the figures for each channel you want to compare.
- Product and packaging cost, shared across all channels
- Selling price in each channel
- Fees, fulfillment, shipping and acquisition per channel
Calculation results
Best channel profit
—
Per order, with the costs you declared.
Winning channel—The one that leaves most per order
Winning channel margin—
Difference per order—Best channel against the second
Difference over 10 orders—
Difference over 100 orders—
Percentage difference—
| Channel 1 | Channel 2 | Channel 3 | Channel 4 | |
|---|---|---|---|---|
| Channel | — | — | — | — |
| Revenue | — | — | — | — |
| Fee | — | — | — | — |
| Processing | — | — | — | — |
| Total fees | — | — | — | — |
| Other costs | — | — | — | — |
| Total costs | — | — | — | — |
| Profit | — | — | — | — |
| Margin | — | — | — | — |
| Maximum CAC | — | — | — | — |
See the breakdown
| Product cost | — |
| Packaging | — |
| Difference per order | — |
| Difference over 100 orders | — |
Recommended next step
The comparison is worth only as much as the costs you entered. If you have never broken down that product's contribution, do it: one forgotten cost can change the winner.
Break down my contribution marginResults are estimates based on the information you enter. Fees, taxes and platform terms can change: always check the figure that matters to you against your invoice or the official platform. They do not replace your real invoices, your official accounts or professional tax, financial or legal advice.
What this tool works out
This sales channel profitability calculator takes one product and pits it across several channels at once, working out for each what survives the order after all its costs.
The condition for the comparison to be valid is that it is the same product. Comparing your most expensive item in one channel against your cheapest in another does not compare channels: it compares products.
Shared costs and channel costs
Product cost and packaging are shared: you pay them wherever you sell, so they are entered once and applied to every channel equally.
Everything else belongs to each channel and is where the real differences show up: the percentage fee, the flat fee, payment processing, fulfillment, the shipping you absorb, acquisition and the returns provision.
That separation is what makes the comparison useful. Fold the shared costs into each channel and the numbers still come out, but you lose sight of where the difference actually lives.
How the formula works
Each channel is calculated separately and then they are ranked by profit.
shared costs = product cost + packaging
For each channel:
fee = price x fee % + flat fee
fees = fee + payment processing
own costs = fees + fulfillment + shipping
+ returns provision + other
profit before CAC = price - shared - own costs
profit = profit before CAC - CAC
margin = profit / price x 100
maximum CAC = profit before CAC (if positive)
difference = best channel profit - runner-up profit
Each channel's maximum CAC is its profit before acquisition: the ceiling on what you can pay for a sale in that specific channel. It usually differs sharply between channels and it is what decides where advertising makes sense.
A worked example
A product with $12 of cost and $1 of packaging. On the own store it sells at $40, with 2.9 % plus $0.35 of gateway fees, $3 of pick and pack, $4 of absorbed shipping, $8 of acquisition and $1.20 of returns provision. On a marketplace it sells at $45, with a 15 % fee, $0.60 of processing, $5 of fulfillment, no absorbed shipping, $4 of acquisition, $1.35 of returns and $0.40 of other costs.
| Item | Value |
|---|---|
| First channel | Own store |
| First channel profit | $9.29 |
| Second channel | Marketplace |
| Second channel profit | $13.90 |
| Difference per order | $4.61 |
| Percentage difference | 49.62% |
| Winning channel | Marketplace |
| Winner's profit | $13.90 USD |
| Winner's margin | 30.89% |
| Difference across 100 orders | $461.00 |
The marketplace wins with $13.90 per order against $9.29 for the own store: $4.61 more per order, a 49.62 % difference. Across a hundred orders that is $461. The marketplace fee is five times larger, but the higher price and cheaper acquisition more than make up for it.
Why there are no preloaded fees
This calculator does not know the fees of Amazon, Etsy or any other marketplace, and that is not an oversight. Rates depend on category, country, product size, logistics program and the plan you are on, and they change without notice.
A preloaded, outdated fee produces a false comparison that looks precise, which is the worst possible combination. Here you enter the fees that appear on your settlement, which are the only ones affecting you.
If you need marketplace precision — weight-banded rates, fulfillment programs, category-specific fee types — use the dedicated calculators for each platform. This comparison is built to choose between channels, not to reproduce one platform's full rate card.
How to read the result
The winning channel is determined by the engine comparing profits, not by position in the table. It is common for the channel with the highest price not to win: a price 12 % higher does not offset a fee five times larger.
The difference per 100 orders is what makes the decision tangible. Four and a half per order sounds like nothing; four hundred and sixty per hundred orders is a different conversation.
Compare the percentage margin against absolute profit too. A channel can leave more money per order with a worse margin, and that matters when your constraint is not demand but cash or available inventory.
What to decide next
The comparison works from each channel's contribution, so its quality depends on the costs you enter being complete. If you have never broken down that product's contribution, it is worth doing first: the returns provision or the packaging are easy to forget, and either can change the winner.
What this assumes
- Exactly the same product is compared across every channel
- Product cost and packaging are identical in every channel
- The fees entered are the ones on your own settlement
- Prices are expressed without indirect taxes
- Each channel sells at the price you entered for it
What it does not cover
- Preloaded fees from Amazon, Etsy or any other marketplace
- The sales volume you would reach in each channel
- Banded, category-specific or weight-based fees
- Fixed monthly subscription charges for a channel
- The cost of running several channels at once
Frequently asked questions
Why are Amazon or Etsy fees not preloaded?
Because they depend on category, country, product size and logistics program, and they change without notice. An outdated rate produces a false comparison that looks precise. Enter the fees from your own settlement, which are the only ones affecting you.
Which costs are shared and which belong to each channel?
Shared: whatever you pay wherever you sell, meaning the product and the packaging. Per channel: everything that changes with where you sell, meaning fees, payment processing, fulfillment, absorbed shipping, acquisition and returns provision.
Can I compare different products in each channel?
You should not: it would stop being a channel comparison. If you sell different references in each place, calculate each product separately and compare their contributions, knowing you are comparing two decisions at once.
Is the highest-billing channel not the most profitable?
Frequently it is not, and that is the reason for this tool. A marketplace may let you charge more and then take a fee that swallows the difference and more. The deciding figure is profit per order, not price and not revenue.
What is each channel's maximum CAC for?
Deciding where and how much to advertise. It is that channel's profit before acquisition, meaning the ceiling on what you can pay for a sale there. It usually differs sharply between channels, and it explains why a bid that is profitable in one ruins the other.
Do I include the marketplace monthly subscription?
Not in this comparison, because it is a fixed cost and this works order by order. To weigh it, divide the subscription by the monthly orders you expect from that channel and compare it against the profit difference per order you see here.
How many channels can I compare?
Two to four: that is this interface's limit, because the comparison table has four columns. If you sell through more, run the comparison in rounds — the first four, then the winner against the next ones — until you have covered them all.
What should I work out after this?
The full contribution breakdown for that product. A channel comparison is only as good as the costs you enter, and packaging or the returns provision are easy to forget: either can change who wins.
Official sources
Shopify — break-even analysis and contribution marginhttps://www.shopify.com/blog/break-even-analysis
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