Last updated 2026-11-08.
These are the rules behind every calculator on the site, includingDepop, Stripe andShopify.
1. Where fee data comes from
Every fee comes from the platform’s own published pages, such as its help center, fee policy or pricing page. We do not use third-party blogs, forums or other calculators as a source for a number. If a platform publishes a fee only in a different region’s version of its page, we say so rather than assume the US figure.
2. What we record for each fee
- The rate or amount, and what it is charged on (for example item price, shipping, tax).
- A link to the official page we read.
- The date we last verified it.
- Any detail the platform does not make clear.
This data is stored in one file per platform. The calculator, the fee table, the worked examples and the change log on a page are all built from that file, so a number cannot differ between the calculator and the text.
3. When a fee is unclear
Platforms do not always say whether a percentage applies to shipping or tax, or how a rule works in an edge case. When that happens we list it on the page as something the platform has not made clear, state the assumption the calculator uses, and avoid guessing beyond that. If a fee is not published, we do not include it.
4. How often we check
We re-check every platform’s fee page at least once a month, and sooner when a platform announces a change. When something changes we update the data, the “verified on” date and the change log on that page. See theeditorial policy for how corrections from readers are handled.
5. How the calculators work
- All calculations run in your browser. The numbers you type are not sent to us.
- The file upload tool runs the same calculator on each row of your CSV or Excel file, using the options you chose in the calculator. The file stays on your device. Rows with a missing, zero or negative price are skipped.
- Fees are calculated from the amounts you enter using the rates in the fee data. Results are shown to the cent.
- “Profit” means what is left after the platform’s fees, your shipping cost and what you paid for the item. It does not include income tax, your time or costs we do not ask about.
- The reverse mode solves the same formula backwards: given the profit you want, it works out the price to charge, including fee caps and minimums where a platform has them.
6. What we do not include
We do not model promotions that platforms can change at any time, custom pricing agreed with individual sellers, or taxes on fees in specific states unless the platform publishes the rate. Each calculator page lists what it leaves out.
7. Limits
The calculators give estimates. Your actual fees can differ if your account has special terms, if a platform changes its fees between our checks, or if a rule applies in a way we did not model. Always compare a result with the fee shown by the platform for a real sale. See our disclaimer.