The problem
Fees change and a quick guess can be wrong. If a seller sends in 100 units of a £16 item and has under-counted fees by £2.50 a unit, that's £250 less profit than planned (100 x £2.50), and the stock is already at the warehouse.
What the AI does
Amazon's UK FBA Revenue Calculator is free to use on its website. You search for an existing product by SKU, title, ISBN, UPC, EAN or ASIN, or define a new one with dimensions, category and weight, and enter the selling price. It compares FBA with fulfilling it yourself and shows net profit per unit and a margin for each, and you can approximate monthly revenue by multiplying the per-unit profit by your expected sales. Amazon says it accounts for referral fees, per-item fees for individual sellers, closing fees, storage and VAT, and that accuracy depends on the information you enter. Before every restock, run the calculator, then compare the margin with your own cost of goods.
A worked example
A seller in Leicester selling kitchen gadgets restocks about 6 products a month. Before each order she runs the product through the calculator instead of using a spreadsheet of fees she last updated in spring.
Before
About 20 minutes a product in a fee spreadsheet: 6 x 20 = 120 minutes, 2 hours a month
After
About 8 minutes a product in the calculator: 6 x 8 = 48 minutes, 0.8 hours a month
What it's worth
About 1.2 hours a month saved (72 minutes), worth around £30 if your time is worth £25 an hour. The calculator is free to use, even without a seller account. The bigger value is catching a bad restock before it happens: £250 on a single order in the example, which isn't counted in the saving. Selling plan costs, £25 a month excluding VAT for Professional, are separate and not part of this use case.
How to set it up
- Open Amazon's FBA Revenue Calculator and search for the product, or define it with its dimensions, weight and category.
- Enter your selling price and compare FBA with fulfilling it yourself.
- Check whether it asks for your product cost; if it doesn't, subtract your landed cost yourself to find true profit.
- Add any fees it doesn't list, such as returns, prep, inbound shipping or advertising, by hand.
- Write down the net profit per unit before you place the order, and set a minimum margin you will not go below.
What goes wrong
- Estimates are only as good as the dimensions, weight and price you enter; Amazon says as much. Weigh and measure a real unit.
- The calculator shows fees, but advertising, returns, prep and shipping to Amazon may not be in the profit figure; add them.
- Fees and storage rates change; recheck before every restock.
- A profit figure per unit says nothing about whether the product will sell; it is only one input.