How the math works

Calculator methodology

Seller Math Hub calculators are designed to be transparent, editable, and conservative. They are planning tools, not professional advice.

Core formula

Gross order revenue = item price times quantity, plus shipping charged to the customer, minus discounts. Estimated profit = gross order revenue minus variable costs, fees, returns, ads, other costs, and optional allocated fixed cost.

Margins and markup

Net margin is estimated profit divided by gross order revenue. Markup on cost is estimated profit divided by total cost basis. The two are related but not interchangeable.

Break-even and target price

Break-even and target-margin prices use the editable percentage fee assumptions and fixed cost assumptions. If percentage costs plus target margin reach 100% or more, the target price is shown as not available.

Privacy model

Calculator math runs in the browser by default. Raw selling price, cost, profit, ad spend, SKU, customer, or account data must not be sent to analytics.

Source review

Fee-sensitive defaults should be recorded in the rate/source ledger with source URL, last-reviewed date, country scope, confidence, known limitations, and next review cadence.