Free seller calculators

Why sellers use these calculators

Marketplace fees quietly eat 10–40% of every sale. A product that looks profitable at a glance can lose money once referral fees, fulfillment, storage, payment processing and ad costs stack up. These tools model the full cost stack so you can price with confidence, compare marketplaces, and spot losing products before you invest in inventory.

Every rate is editable and every default is labeled. Fees change — we track publicly reported 2026 schedules and mark anything we could not verify as an estimate.

How to get a number you can trust

A calculator is only as honest as its inputs, so gather the real figures before you start. You need five: your selling price, what the product costs you landed (unit cost plus inbound shipping), the marketplace fee for your exact category, fulfillment or postage cost, and what you realistically spend on ads per sale. Most of these live in your seller dashboard — check your category referral rate under your fee schedule, your last fulfillment invoice for true per-unit shipping, and your ads console for the cost of your most recent orders rather than a lifetime average.

Then run the numbers at three moments. Before you buy inventory, when a bad margin can still be walked away from. Before you change a price, so you can see whether the new price survives the fee stack or quietly drops below break-even. And every quarter, because marketplaces revise fees, categories get reclassified, and ad costs drift — a product that was profitable in January can be a slow leak by June.

What a calculator can't decide for you

These tools model costs, not demand. A healthy margin on paper does not guarantee the product will sell, that you will win the Buy Box, or that returns will stay low — returns rates, in particular, vary enormously by category and are the cost most new sellers forget entirely. Use the calculators to kill bad ideas cheaply and to price good ideas properly, then validate demand with small test orders before committing to depth. If the numbers only work at a price your market will not pay, that is the calculator doing its job: telling you early.

Go deeper: the guides behind the numbers

Each calculator pairs with a guide that explains the fee stack it models. Amazon sellers should read Amazon FBA fees explained alongside the profit calculator, and the FBA break-even formula walkthrough before using the break-even tool for an Amazon product. TikTok Shop sellers can pair the fee calculator with TikTok Shop fees explained, which breaks down commission and creator costs in plain English. And when you want the same thinking applied across your whole catalog instead of one product at a time, that is exactly what our free store audit does.

New: landed cost and FBA storage calculators

Two costs used to hide outside the marketplace calculators, so we built tools for them. The import duty & landed cost calculator answers the question every importer now has to ask since the end of duty-free de minimis shipments: what does one unit truly cost once product, freight, insurance, customs duty, extra tariffs, brokerage and domestic delivery are all counted? Enter your own duty rate — rates depend on your exact HS code and origin, so the tool never pretends to know it for you — and get a landed cost per unit plus a gross margin check at your planned selling price.

The Amazon FBA storage fee calculator isolates the fee sellers feel last: warehouse rent. Give it your item dimensions or cubic feet, units and months in storage, and it returns monthly storage cost, the total for the period and a per-unit figure — including the aged inventory surcharge that lands on stock sitting past 181 days. Rates are prefilled as clearly labeled examples and every rate field is editable, because Amazon revises this schedule and your Seller Central account is the final word.