Live: https://lowlune.github.io/feescope/
FeeScope estimates the fees a marketplace charges and what you actually keep. Enter a sale price and cost, pick a marketplace, and see itemized fees, net proceeds, profit, margin, ROI, and the break-even price.
- No signup, no tracking, no server — all math runs in your browser.
- Shareable URLs: every input is saved in the query string.
- CSV export of the itemized results.
- Every rate is configurable, so you can update a marketplace's schedule when it changes.
Etsy · eBay · Amazon FBA · Poshmark · Depop · Shopify · custom
- Reseller fee & profit calculator — all marketplaces
- Etsy fee calculator
- eBay fee calculator
- Amazon FBA calculator
- Print-on-demand profit calculator
- Poshmark fee calculator
- Depop fee calculator
- Shopify fee calculator
Each landing page's worked example is computed at build time by the same tested engine.
node test-fees.mjs # 66 assertions over the fee engine (all marketplaces + custom)
node check-ids.mjs # verifies every element id the UI expects is presentMarketplace fee schedules change over time; every rate is editable in the app and the defaults
are documented with their simplifications in fees.js.
python3 -m http.server 8000 # then open http://localhost:8000index.html— the free calculator appfees.js— pure, tested fee engine (marketplace profiles + custom)app.js— UI wiring, itemized results, CSV export*-calculator.html— SEO landing pages with build-time worked examplesstyles.css
FeeScope Pro is an offline, self-contained HTML batch console: import a CSV catalog, compute itemized fees, profit, margin and ROI per row, solve the break-even price per SKU, and price to a target profit or margin across all supported marketplaces with a sortable comparison table. It is a separate paid download; this repository contains only the free web tool.
- RentScope — free rental property calculator.
Educational estimation only — marketplace rates are approximate and configurable; not tax or accounting advice.
MIT licensed (free web tool only).