Methodology / version 2026-09-01

The math stays visible.

Every result begins with seller-supplied inputs. Money is calculated at fixed precision, then displayed to the nearest cent unless an official fee requires per-line cent rounding.

Profit model

Net profit = revenue − product costs − fulfillment − payment fees − platform fees − expected return loss − ads − other costs − allocated fixed costs

Revenue is item price times quantity, plus charged shipping, less discounts. Net margin is net profit divided by revenue; when revenue is zero, margin is shown as unavailable.

Pricing model

Required revenue = fixed dollar costs ÷ (1 − percentage fee rate − target margin)

The displayed minimum unit price is rounded upward to the next cent. This prevents ordinary nearest-cent rounding from dropping the result below the requested margin.

Advertising model

Break-even ad spend = revenue − non-ad costs
Break-even ROAS = revenue ÷ break-even ad spend

If non-ad costs already consume all revenue, no positive break-even ROAS exists. Amazon ACoS uses ad spend divided by ad-attributed sales; ROAS uses the reciprocal inputs. TACoS is shown as a planning ratio, not described as an Amazon-official metric.

Limits

Results are estimates, not accounting, tax, or legal advice.
Actual processor statements may use different rounding, reserves, taxes, refunds, or regional rates.
The Amazon tool does not estimate referral, FBA, storage, or closing fees.
The Etsy tool currently models the verified US fee set only.