A marketplace profit calculator shows what each order earns after product costs, fees, fulfillment, advertising, and allocated overhead. Its result is only useful when you include every applicable cost, rather than stopping at the marketplace payout.
An initial calculation gives you a view of a product’s unit economics, but storage charges or refunds can change the result. Start with revenue you retain, then build a consistent cost model for each product and sales channel.
Key Takeaways
- Calculate order profit after fees, shipping, fulfillment, advertising, returns, and overhead.
- Keep contribution margin separate from net margin so you don’t subtract fixed costs twice.
- Compare marketplaces using the same product and selling price, with channel-specific costs.
Set Up Your Marketplace Profitability Calculator
Start with retained revenue
Use the selling price after discounts, not the undiscounted list price. Include customer-paid shipping as revenue, then subtract your full shipping costs. Exclude sales tax collected for remittance.
For example, $6 collected for shipping against a $9 carrier charge creates a $3 shipping subsidy. Record both amounts or subtract the subsidy from product revenue, but don’t do both.
Capture the complete cost stack
Enter each product’s per-unit COGS (cost of goods sold), inbound freight, packaging, outbound shipping, fulfillment labor, storage, advertising, and return-related costs. Add monthly subscriptions and other overhead separately.
Avoid counting inbound freight twice if your landed COGS already includes it. Likewise, separate marketplace commissions from payment processing.
Amazon’s category-specific referral marketplace fee commonly ranges from 8% to 15%, but category rules vary. Its selling fee schedule also includes tiered rates and minimums. FBA adds fulfillment charges based on size and weight, plus storage and applicable inventory charges.
Calculate Profit, Margin, and Markup
Apply fees before calculating profit
Payment processing fees = Revenue × Fee rate ÷ 100 + Fixed fee
Apply the percentage to the full revenue amount entered. If the processor also charges on collected tax, calculate that fee separately without treating tax as sales revenue.
Net profit per order = Revenue − (COGS + Inbound shipping + Marketplace fees + Payment processing + Fulfillment + Storage + Returns + Advertising + Overhead)
The figure is only net of the costs included.
Profit margin % = Profit ÷ Revenue × 100
Return on included costs % = Profit ÷ Total costs × 100
These ratios divide the same profit by different amounts.
Keep markup and margin separate
Markup measures profit against cost. Margin measures profit against the sell price.
Sell price = Total unit cost × (1 + Markup rate)
A $28 total cost per unit with 100% markup produces a $56 price and 50% margin. Markup exceeds margin when both use the same positive profit.
Gross margin subtracts only COGS. Contribution margin subtracts variable costs, while net margin also deducts overhead and other applicable expenses. Our ecommerce contribution margin calculator keeps order economics separate from fixed operating costs.
Work Through a $100 Order
This calculation uses the specified inputs without a marketplace referral fee or separate storage and returns allowance.
| Input or result | Amount |
|---|---|
| Revenue | $100.00 |
| Product cost | $40.00 |
| Delivery | $8.00 |
| Advertising | $12.00 |
| Other costs | $2.00 |
| Payment fees at 2.9% + $0.30 | $3.20 |
| Total costs | $65.20 |
| Profit after included costs | $34.80 |
| Profit margin | 34.80% |
| Return on included costs | 53.37% |
The payment calculation is $100 × 0.029 + $0.30 = $3.20. Subtracting $65.20 from revenue leaves $34.80.
Stripe’s domestic card pricing uses that processing structure. On a $30 transaction, it costs $1.17, or 3.9%, because the fixed charge increases the effective rate.
The 34.80% profit margin reflects only the costs listed, so $34.80 isn’t fully loaded marketplace profit. A 15% referral fee alone would reduce it to $19.80.
Allocate Advertising, Storage, and Returns Consistently
Assign costs to the orders that generate them
A $600 ad spend allocated as advertising costs across 50 orders equals $12 per order. Entering the entire $600 against one order distorts that order’s estimate.
Include Amazon PPC, branded search, retargeting, influencer payments, and applicable agency costs. Use 12% and 25% of revenue as advertising sensitivity cases, not universal spending benchmarks.
For SKU reporting, allocate campaign spending to associated products. Allocate shared advertising consistently rather than changing attribution methods between months.
Storage needs a different allocation. Bulky, slow-moving inventory consumes more space and time than compact, fast-selling stock. Assign storage using occupied volume and holding time where possible. Spread shared subscriptions across the same reporting period.
Model refunds without double-counting losses
Stress-test a 5% or 10% return rate, plus 20% and 30% scenarios for apparel. Treat these as scenarios until your own return history supports an estimate.
At a 10% full-refund rate, the $100 example retains $90 revenue per original order. If returned stock is unsellable, the original $40 COGS remains. Profit falls to $24.80 before additional return postage, handling, restocking, or fee credits.
Recoverable inventory changes that result. Record its recoverable value, then add reverse-logistics expenses.
If revenue already excludes refunds, don’t subtract those refunds again as a returns reserve.
Compare Marketplaces and Fulfillment Methods
Compare channel-specific unit economics while keeping the product, $100 selling price, destination, and reporting period constant. Then change only channel-specific inputs.
These options require different cost fields.
| Channel and method | Selling fees | Fulfillment costs to include |
|---|---|---|
| Amazon FBA | Category referral fee (marketplace fee) and selling-plan allocation | FBA fee, inbound placement, freight, storage, applicable inventory charges |
| Amazon seller-fulfilled | Category referral fee and selling-plan allocation | Postage, packaging, labor, storage |
| Shopify self-fulfilled | Processing and subscription allocation; applicable third-party transaction fees | Postage, packaging, labor, storage |
Shopify is an owned storefront, not a marketplace, but it provides a useful comparison. Its US standard-card rates are 2.9% + $0.30 on Basic, 2.7% + $0.30 on Grow, and 2.5% + $0.30 on Advanced.
For Amazon orders, don’t automatically add a standalone card-processing charge on top of referral fees.
Compare both contribution dollars and fully allocated profit. Self-fulfillment may save service fees but consume paid labor. Marketplace-managed fulfillment may reduce handling work while adding inventory expenses.
Across a catalog, divide combined profit by combined revenue. A simple average of SKU margins gives low-volume products too much influence.
Find Break-Even Pricing and Monthly Order Volume
Solve for the minimum selling price
To find the minimum sell price, account for the fact that percentage fees change when the price changes. Adding today’s fee to costs won’t give an accurate break-even price.
Break-even price = (Non-percentage costs + Fixed transaction fee) ÷ (1 − Combined percentage fee rate)
For the worked example, non-processing costs total $62:
($62 + $0.30) ÷ (1 − 0.029) = $64.16
This breakeven price assumes unchanged costs and no referral fee. Add applicable percentage commissions to the denominator’s fee rate. To target a margin, subtract that margin rate from the denominator too.
Calculate orders needed to cover fixed costs
Monthly break-even orders = Monthly fixed costs ÷ Profit per order before fixed overhead
Here, “profit per order” means contribution after variable costs, including advertising. Don’t divide fixed costs by a figure that already deducts those same costs.
Round the answer up to a whole order. If contribution is zero or negative, no finite sales volume covers fixed expenses.
For multiple products, use contribution weighted by the expected sales mix.
Use the Results to Set Pricing and Advertising Limits
Assess ecommerce margin against your own target. Use 15% to 25% net margin as a planning range, with 30% or more potentially representing a healthy margin for premium positioning. These aren’t universal category benchmarks. Below 10% net margin, fee changes or refunds can consume much of the remaining profit.
For a new product, model launch pricing alongside higher acquisition costs and return rates. Then update the inputs as orders mature.
Advertising needs a separate floor:
Break-even ROAS = 1 ÷ Pre-ad contribution margin ratio
A 40% pre-ad margin requires 2.5x ROAS. Advertising consumes the available contribution at that threshold, leaving nothing for overhead. Our break-even ROAS guide explains how to set a higher operating target.
Fee schedules also change. Amazon’s 2026 FBA fee notice includes a 3.5% fuel and logistics surcharge on fulfillment fees starting April 17, 2026. That isn’t 3.5% of sales revenue.
Recalculate when costs change. An extra charge equal to 1% to 3% of revenue removes one to three margin percentage points.
Frequently Asked Questions
What markup should I use for a new product?
Choose markup after calculating the price needed to cover costs and your target margin. A blanket 100% markup produces 50% margin only when the cost base includes every applicable expense.
Demand still limits achievable pricing. Compare the calculated floor with competing offers and your product’s positioning. If buyers won’t support that price, reduce costs or reconsider the offer.
Does changing currency convert the calculator’s amounts?
A currency selector may only change the displayed symbol. Conversion requires an exchange rate applied to every relevant amount.
Keep revenue and expenses in one reporting currency. Also include conversion fees and differences between transaction and settlement rates. Mixing dollar revenue with euro costs produces a meaningless result, even when the arithmetic works.
Make Every Order Earn Its Place
A useful profitability calculation connects retained revenue with the full cost of selling and delivering an order. Keep contribution and net profit separate, then compare channels using consistent assumptions.
Use the result to set a price floor, choose fulfillment, and limit advertising spend. Revenue growth helps only when additional orders leave enough money behind.
