How to Calculate Your True Profit Margin After Marketplace Fees

A lot of sellers price products based on selling price minus product cost, see a healthy-looking margin, and then wonder months later why the business doesn’t feel as profitable as the spreadsheet suggested. The gap is almost always marketplace fees that never made it into the original calculation.

A realistic per-order margin needs to subtract, in addition to product cost: commission (category-specific, not a flat assumption), shipping or logistics fees (which vary by weight and zone, not a flat per-order estimate), TCS (1%, recoverable as GST credit but still a cash-flow timing cost), and an amortized allowance for returns — not zero, since some percentage of orders will come back regardless of category.

The return allowance is the piece most sellers skip entirely. If your category runs a 10% return rate and a return costs you the original commission plus a reverse shipping fee, that cost needs to be spread across all orders in your margin math, not treated as a one-off loss when it happens.

The only way to get these numbers right instead of estimating them is working backward from actual settlement data — pulling your real average commission rate, real average shipping cost, and real return rate for a category over the last few months, rather than using the headline rate-card numbers, which don’t account for how weight-slab or category-tier variance actually plays out on your specific catalog.

Once you have real, settlement-derived averages per category, pricing decisions get a lot more reliable — and it becomes obvious which SKUs are quietly running at breakeven or a loss once every fee is actually accounted for, not just the ones you can see on the surface.