About Marginely
Marginely publishes free calculators that show what a marketplace sale actually costs. It is published by Marginely Editorial. We publish under that name rather than individual bylines, and we claim no professional qualification in accounting, tax or logistics.
Who this is for
The tools are for the moment a price is being set or a shipment is being planned: a seller deciding whether a SKU still clears its fees after the next fee revision, someone comparing fulfilment against merchant shipping, or a shipper checking whether a surcharge applies before quoting a customer. They cover Amazon referral and FBA fulfilment fees, currency conversion, reimbursements and inbound placement, Walmart and TikTok Shop fees, FedEx and UPS surcharges, and the review checklists for hazmat, ungating and FBA shipments.
Every calculator is free, needs no signup and runs in your browser, and they can be embedded on another site at no charge. What you type into a calculator is not sent to us — the privacy note sets out what the site does and does not collect.
What Marginely is not
We are not affiliated with, endorsed by or compensated by Amazon, Walmart, TikTok Shop, FedEx or UPS. We are not accountants, tax advisers, customs brokers or freight forwarders, and nothing here is financial, tax or legal advice. Using the site creates no advisory relationship.
A result is an estimate built from a published schedule, not a copy of your invoice. Account-level negotiated rates, size-tier and dimensional-weight measurement, promotional or programme discounts, and what a marketplace actually settles for a specific claim can all move the real number. We do not review individual seller accounts and cannot tell you what a marketplace will decide in your case.
How the numbers are made and checked
Rates come from the schedule-setter's own published material: Amazon's selling-partner fee announcements and Seller Central fee tables, Walmart's and TikTok Shop's published seller pricing, and the carriers' own rate and service guides — including the rate PDF where a carrier renders its amount table in JavaScript. Seller blogs, agency summaries and forum anecdotes are not used as the source of a rate.
Two automatic checks run without us. A fee watcher for each marketplace and for shipping re-reads the published schedules on its own monthly cycle and reports when the page changes. A separate audit runs every Friday, re-reads the sources linked from each page and checks every figure shown against them; where a figure is not found, we find the source, correct the figure or remove the statement.
Not every number is a sourced one. Worked examples, a calculator's starting values and assumptions a page states as its own are ours, and so are estimates of private costs — what a prep centre or a 3PL charges, for instance — which no marketplace schedule sets. Those are outside the source check, because no source carries them. Drafts are written with the help of AI tools, and a figure we add or change is checked against the published schedule before it goes up.
How Marginely is funded
The site is supported by advertising through Google AdSense. Affiliate placements exist in the page templates but are switched off at present; if one is switched on, the commission disclosure appears beside the link. No payment is accepted to change a rate, a threshold or the order of a comparison, and advertisers have no input into what a page says or what the audit flags.
Corrections
If a fee no longer matches what a marketplace charges you, tell us through the contact form. A report that names the tool, the figure and the published schedule you are reading is the one we can act on directly.