Short answer: beginners subtract the product cost from the sale price and call the difference profit. Amazon typically takes 30 to 45 percent of the sale price before you pay for the product at all. The number that matters is what lands in your account after the full fee stack, and most people never build that stack. I run Vela K Products Ltd., a Canadian distribution company selling on Amazon in Canada and the USA, and this is the calculation we run before buying anything.

The mistake, in one line

A seller finds a product selling for $30 that they can buy for $12. They see $18 and think they have found a winner. In reality Amazon takes its cut first, and the $18 is usually closer to $6 or $7 once every fee is counted. On thinner products, it can be nothing.

This is not a small rounding error. It is the difference between a catalogue that funds itself and one that quietly loses money on every single order while looking busy.

The fee stack Amazon actually charges

Fees are not one percentage. They are a stack, and each layer has to be in your maths.

• Referral fee. Amazon's commission on the sale. Most categories sit at 15 percent, with the wider range running from roughly 5 to 45 percent depending on category, and some categories using tiered rates by price.
• FBA fulfilment fee. Charged per unit based on size and weight. Standard-size items commonly land somewhere around $3 to $7 per unit.
• Fuel and logistics surcharge. As of April 17, 2026, Amazon applies a 3.5 percent surcharge calculated on the fulfilment fee in the US and Canada.
• Monthly storage. Charged by cubic foot and higher in the fourth quarter.
• Long-term storage surcharges. Inventory sitting past roughly 181 days starts collecting extra charges, and it gets worse the longer it sits.
• The Professional selling plan. A monthly subscription that has to be spread across the units you actually sell.

The costs that are not Amazon fees, and still hit you

Even sellers who count Amazon's fees often stop there. These are yours to carry.

• Inbound shipping to get your stock to Amazon's warehouse.
• Prep and labelling, whether you pay a prep centre or do it yourself.
• Returns. When a customer returns an item, Amazon refunds part of the referral fee, but the fulfilment fee is not coming back. Some returns come back unsellable, which is a straight loss.
• Advertising. If you run ads, that cost belongs against the units it sold.
• Your own capital. Money tied up in stock that is not moving is not available for stock that is.

The calculation that actually works

Write it as a subtraction chain and do it before you place the order, not after.

Sale price, minus referral fee, minus fulfilment fee and surcharge, minus product cost, minus inbound shipping, minus prep, minus an allocation for storage, minus an allowance for returns, minus advertising. Whatever survives that is your profit per unit.

Then divide it by the sale price. That percentage is your margin, and it is the only number worth comparing across products. A big dollar figure on a slow, bulky, high-return item can be worth less than a small one on a product that turns over quickly.

Why this is where most people quit or lose money

Running this properly on one product takes a few minutes. Running it across a supplier price list with thousands of lines is not something anyone does by hand, which is why sellers use a calculator or a bulk analysis tool before committing capital.

The sellers who last are not necessarily better at finding products. They know exactly what Amazon will take before they buy a single unit. The ones who struggle are guessing, and then wondering why a full warehouse has not produced any money.

Common questions

How much does Amazon take per sale? Commonly 30 to 45 percent of the sale price once referral, fulfilment, storage and the surcharge are combined. Low-priced items can be worse in percentage terms.

Is there a free way to check? Yes. Amazon publishes a fee calculator, and the current referral schedule is in Seller Central. Check the live figures rather than trusting an article, including this one, because fees change.

Does FBM avoid this? It avoids the fulfilment and storage fees, but not the referral fee, and you take on shipping and customer service yourself. It suits large, slow or awkward items more than fast-moving ones.

What margin should I look for? There is no universal number, and anyone quoting one is guessing about your capital and category. What matters is that the margin survives the full stack above and the product turns over fast enough to recycle your money.

The short version

Profit is not sale price minus cost. It is what remains after a stack of fees that Amazon publishes openly and most beginners never add up. Build the stack once, apply it to every product before you buy, and the business stops surprising you.

We teach the brand-direct wholesale model we run ourselves at Vela K Products Ltd. If you want to see how we evaluate products before buying, the free starter training walks through it.