About CartMargin

Most margin calculators stop at "price minus cost." CartMargin adds the pieces that actually decide whether an order was worth taking: advertising cost, payment and platform fees, shipping, discounts, and returns — all in one calculation, so you can see what an order really earns.

Who it's for

CartMargin is built for people who run online stores and have to make pricing and ad-spend decisions themselves: independent Shopify and WooCommerce sellers, DTC brands, dropshippers, digital product sellers, and the marketers and agencies who run ads for them.

What it won't do

• It won't guess your country's tax rate or a specific platform's current fee schedule — those change often and getting them wrong quietly would be worse than asking you to enter them.
• It won't ask you to create an account or store your numbers anywhere.
• It won't give pricing advice — it shows you the math so you can decide.

How it's maintained

The calculation formulas are documented on the Methodology page and kept in sync with the code that runs the calculator. If you find a calculation that looks wrong, let us know — a formula error is treated as a bug, not a rounding footnote.