Selling on a marketplace changes the maths: the platform takes a commission, charges for fulfillment and storage, and returns quietly eat into every shipped unit. This guide shows how to build a marketplace seller's unit economics — from sell price down to real profit per order — with a worked example and a free calculator to model your own numbers.
Model your marketplace unit economics free →Why a marketplace is different from your own store
On your own site you keep the whole price minus cost and shipping. On a marketplace, the platform sits between you and the buyer and takes a cut at several points: a category commission, fulfillment and last-mile logistics, storage, and often a share of promotions. Model all of them or the unit looks far more profitable than it is.
The commission bite (Ozon, Wildberries, Yandex Market)
Every marketplace charges a category commission — a percentage of the sale price. It varies widely by category, from a few percent on some electronics to roughly 20–25% on apparel and accessories, and platforms adjust the rates over time.
Treat the headline commission as just the first fee. Check the exact current percentage for your category in your seller dashboard rather than assuming — then put that number into the calculator's commission field.
Fulfillment model: who moves the box (FBO vs FBS)
Under a marketplace-fulfilled model (Ozon FBO, Wildberries's warehouse, Yandex Market FBY) the platform stores and ships your stock and bills you for storage plus per-order logistics. Under a seller-fulfilled model (FBS) you hold the stock and pack each order, but still pay last-mile delivery.
Either way there's a per-order logistics cost and, for warehouse models, a storage cost that grows the longer stock sits. Weight and package size drive the logistics fee — a heavier or bulkier 'big pack' costs more to move than a small one.
Returns and the effective cost per order
A returned item usually still costs you the outbound and return logistics, and sometimes handling or repackaging — even though you keep no revenue on it. So the real cost per shipped unit is higher than a single happy-path order suggests.
The practical way to model this: take your return rate and spread the round-trip logistics of returned units across the orders that actually sell. A 10% return rate on a low-margin item can be the difference between profit and loss.
Promotions and discounts eat margin fastest
Marketplace sales events push you to discount, and the discount comes straight off your margin — commission is charged on the discounted price, but your cost of goods doesn't shrink. Before joining a promo, check your break-even price: the sell price at which profit per unit hits zero. Discount below it and every extra order loses money.
A worked example
Say you sell an item for 2,000 with a cost of goods of 900. The category commission is 17% (340), fulfillment and last-mile logistics are 250 per order, packaging 30, ads average 120 per unit, and tax on the sale is 6% (120).
Add the costs: 900 + 340 + 250 + 30 + 120 + 120 = 1,760. Profit per order is 2,000 − 1,760 = 240, a 12% margin. Now layer a 10% return rate: the round-trip logistics on returned units pulls the real profit down further — which is exactly the kind of adjustment the calculator makes for you.
Frequently asked questions
What commission does Ozon, Wildberries or Yandex Market take?+
It depends entirely on the category and changes over time — anywhere from a few percent to about 20–25%. Always read the current rate for your specific category in the platform's seller dashboard, then model it; don't rely on a single quoted number.
Should I include storage and returns in unit economics?+
Yes. Storage is a real per-unit cost the longer stock sits, and returns cost you round-trip logistics with no revenue. Leaving either out overstates profit per unit.
What's the difference between FBO and FBS?+
FBO/FBY means the marketplace stores and ships your stock (you pay storage plus logistics); FBS means you hold and pack stock yourself but still pay last-mile delivery. Both carry a per-order logistics cost to model.
How do I find my break-even price?+
It's the sell price where profit per unit reaches zero after every fee. Knowing it tells you how deep you can discount in a promotion before each order starts losing money — the calculator reports it for you.
The iznkit editorial team builds and documents free, no-sign-up tools for freelancers, small businesses and developers — and writes these guides to go with them.
About iznkit →