MarginWatch

Amazon on-page profit calculator with editable cost and fee inputs

MarginWatch is a lightweight Chrome extension that helps Amazon sellers estimate profitability directly on Amazon product pages. Instead of switching between product listings, notes, spreadsheets, and separate calculators, MarginWatch keeps the analysis where the decision happens: on the product page itself. With MarginWatch, you can quickly review: - product price - product cost - shipping cost - FBA fee - referral fee - estimated profit - ROI - break-even price What MarginWatch does - works directly on supported Amazon product pages - lets you edit your cost and fee assumptions - updates calculations on-page - helps you do fast first-pass product checks Why MarginWatch MarginWatch is built for sellers who want a simple and practical way to evaluate products without slowing down their workflow. It is designed to make quick profitability checks easier while keeping the inputs flexible. Current scope MarginWatch currently focuses on Amazon on-page profit calculation. It is not a price history tracker, competitor monitor, or alerts platform in its current version. Important note All calculations are estimates based on the product price detected on the page and the values you enter. Actual Amazon fees, payouts, taxes, category fees, and fulfillment costs may vary.