Methodology
Every calculator on this site uses the same four-step model. It is deliberately simple so that you can check it by hand.
The model
- Fee base. Revenue is the item price plus shipping charged to the buyer, multiplied by the number of units.
- Fees. Each published fee is applied to that base: a percentage, a percentage plus a fixed amount, a flat amount per item, or a size-tier amount for fulfilment.
- Costs. Item cost, actual postage and monthly fixed costs (subscriptions, ad spend) are subtracted.
- Result. Net profit, per unit and in total, plus the effective fee rate and the break-even price.
Assumptions worth knowing
- One unit = one order. Fixed per-order fees are charged once per unit. If your orders usually contain multiple items, your real fixed-fee cost is lower than shown.
- No sales tax or VAT. Tax collected by the platform is not your revenue and is excluded entirely.
- No returns or chargebacks. Both cost real money; add a few percent to item cost if returns are common in your category.
- No currency conversion. If you sell in one currency and get paid in another, the platform's conversion spread is an additional cost not modelled here.
- Optional fees are off by default. Ad attribution fees only apply to a share of orders, so they are a switch rather than a constant.
Verification
Each platform/region pair carries a status. Verified means every line was matched against the linked source page on the date shown. Draft means the numbers are our best current understanding but have not been confirmed line by line. The status is displayed on the calculator page itself, not buried in a changelog.
Rates are re-checked when a platform announces a change and at least once a year otherwise. The fee tracker shows the current state of the whole dataset.
Limits
These are estimates for planning, not accounting records. Your actual payout is whatever the platform's invoice says. Where the two disagree, the invoice wins.