Free tools

Calculators that show their working.

Short answer

Three free calculators for sellers pricing real inventory: profit margin and markup on any product, Amazon FBA profit after referral and fulfillment fees, and dropshipping profit with the break-even ROAS your campaigns have to beat. No signup, and every formula is written out on the page.

The calculators

Profit margin calculatorGross margin, net margin, markup and ROI on any product, plus the price that hits a target margin.Amazon FBA profit calculatorReal FBA profit, margin, ROI and break-even ACoS after referral fees, fulfillment, storage, ads and returns.Dropshipping profit calculatorProfit per order, margin, ROI and break-even ROAS after product cost, shipping, fees, ads and returns.

Why the arithmetic is written down

A calculator that hands you a number and hides the formula is asking you to trust it with a pricing decision. These pages do the opposite: each one lists the formula it used, the source the rates came from, and the places where Amazon's own published documentation contradicts itself. Where an assumption had to be made, it is labelled as an assumption.

The Amazon calculator is built on the 2026 US referral fee table and FBA rate cards from Seller Central and sell.amazon.com. Its fee engine reproduces every worked example Amazon publishes - fulfillment fees for a mobile device case, a t-shirt, an iron, a baby cot, a monitor and a TV, at both peak and non-peak rates, plus both monthly storage examples - to the cent.

A margin is only as good as the fees that have not changed yet.

These calculators price the fees Amazon charges today. Notifcentral tells you when they change - FBA fee changes, Buy Box loss, listing suppressions and account health, straight to your phone.

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notifcentral

Fee changes, buy box, listing issues, held funds, reimbursement recovery, payout confirmations - delivered to your phone before any of it costs you money.

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