Margin Ruler

Break-Even Ad Spend Calculator

Given product margin, average order value, target ROAS, and conversion rate, this calculator returns true-ROAS CPA, profit-safe max CPA, break-even ROAS, …

Amazon FBA is active. Other marketplace modules stay marked as planned until audited.

Real Amazon fees, dated to sourceNo account or emailPrivate unless you save
Methodology

Break-Even Ad Spend Calculator. Computes true-ROAS CPA from revenue ÷ ad spend, then caps max CPA at gross-profit break-even when the target ROAS is below break-even.

Fee schedule/source date: ad-spend economics model reviewed 2026-05-08; compare with live platform CPCs before acting.

Read the formula, inclusions, exclusions, and fee-category audit →

Calculator
Regional pages

Regional pages

Margin Ruler keeps a regional page for every active country so calculators stay tied to the local landing context. Browse below; the calculator math is the same on each.

Australia

Canada

New Zealand

United States