Free Tools for E-commerce Sellers
Profit margin, marketplace fees, shipping costs, and break-even math — the numbers behind selling something online, without guessing.
Selling online — whether on Amazon, Etsy, Shopify, or your own site — comes down to a handful of numbers that are easy to get wrong if you're doing the math in your head. Four calculators cover the core ones.
What's your actual margin?
The Profit Margin Calculator works both directions: tell it your cost and price to find your margin and markup, or tell it your cost and a target margin to find the price you need to charge.
What do marketplace fees actually take?
Amazon, Etsy, eBay, and Shopify all take a cut differently, and their fee structures are tiered and change over time — so rather than hardcoding numbers that could go stale, the Marketplace Fee Calculator gives you an editable starting-point percentage and computes your real net profit once you enter your actual current rate.
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Shipping and break-even
The Shipping Cost Estimator factors in dimensional weight (the box-size-based charge that catches a lot of sellers off guard), and the Break-Even Calculator tells you exactly how many units you need to sell before you're actually making money.
Run the Break-Even Calculator before you finalize pricing, not after — it's a lot easier to adjust a price on paper than to explain a price change to existing customers.