Seller toolkits
Calculator clusters for common seller workflows.
Tools and checklists for profit, fees, shipping, offers, and break-even listing decisions.
RotoCurveAmazon Seller ToolkitTools and checklists for referral fees, FBA or FBM assumptions, ads, and unit economics.
RotoCurveEtsy Seller ToolkitTools and checklists for listing fees, transaction fees, handmade margins, shipping, and coupons.
RotoCurvePoshmark Seller ToolkitTools and checklists for seller fees, offers, shipping discounts, and clothing resale margin.
RotoCurveShopify Store ToolkitTools and checklists for payment fees, AOV, conversion rate, ROAS, and free-shipping thresholds.
RotoCurveShipping Cost ToolkitTools and checklists for dimensional weight, zone cost, markups, fuel, insurance, and thresholds.
Quality and usage notes
This page is intended to help users make clearer planning decisions with transparent assumptions. Results are estimates and should be checked against official sources when money, taxes, shipping, or marketplace rules are involved.
How to use this page well
Use this page as a planning aid, not a final quote or official rule. Replace defaults with your own numbers, compare more than one scenario, and check any important fee, tax, carrier, or marketplace policy against the official source before acting.
- Use real costs instead of rounded guesses whenever possible.
- Review the result together with shipping, returns, discounts, taxes, and payment fees.
- Save or repeat the calculation when costs change, because small inputs can change profit quickly.