Useful calculators with the assumptions shown.
Fair Calcs builds focused tools for decisions people make every day. Each calculator explains what it includes, links to important sources, and keeps inputs on the current device unless stated otherwise.
Resale profit calculatorEstimate profit, fees, margin, ROI, and break-even price.
Minimum offer calculatorFind the lowest sale price that still reaches a target profit.
Maximum buy priceFind the most you can pay while preserving a target profit.
eBay fee calculatorStart with reviewed eBay fee assumptions and add real costs.
Poshmark fee calculatorHandle the flat and percentage commission threshold.
Mercari fee calculatorEstimate fees and net profit under current inputs.
Etsy profit calculatorCombine listing, transaction, payment, and fulfillment costs.
Fair does not mean guaranteed
Fees, laws, rates, and marketplace rules change. Fair Calcs shows the current assumptions and lets users change them. Results remain estimates, not financial, tax, legal, or professional advice.