About Seller Margin Lab
Seller Margin Lab is four calculators for one question: what does a single order really earn? The general profit margin calculator works for any channel; the Amazon FBA, Etsy and landed-cost calculators lay out the fees and import costs specific to each.
How it works
Everything is calculated in your web browser. Each calculator shows profit, margin and ROI per order, the break-even item price, the price for a target margin, the most you can pay per unit at your current price, and a table of what other prices would earn. The starting numbers are an example; fees change, so replace them with your own current figures.
An optional sign-in is available; the calculators work without an account.
Who makes it
Seller Margin Lab is part of Toolwoven, a small independent collection of free browser tools. Each tool focuses on one practical task.
Read the privacy notice for details on storage, the optional account and analytics.
Last updated: 19 October 2026