This free calculator shows exactly what you keep from each sale after platform fees, fixed fees, product cost and shipping are deducted. It is built for sellers and small business owners who want a clear picture of their costs per order before setting prices or planning margins.
Free version: it runs in your browser — nothing you type leaves your device.
How to use the free calculator
- Enter the selling price for one item.
- Add the platform fee percentage and the fixed fee charged per order.
- Enter your product cost and shipping cost per sale.
- Read your net profit per sale and real margin, which update as you type.
- Copy or print the result if you want to keep a record.
How the calculation works
The calculator takes your selling price and subtracts every cost tied to a single sale: the percentage-based platform fee, the fixed fee per order, the product cost and the shipping cost. What remains is your net profit per sale. Dividing that net profit by the selling price gives your real margin, expressed as a percentage.
In plain words, the formula is: net profit equals selling price minus platform fee minus fixed fee minus product cost minus shipping cost. Real margin equals net profit divided by selling price, multiplied by 100. The tool also lists gross revenue and each cost line separately so you can see where the money goes.
A worked example with round numbers: a selling price of 50, a platform fee of 10 percent (5), a fixed fee of 1, a product cost of 20 and shipping of 5. Total costs come to 31, so net profit per sale is 19 and the real margin is 38 percent of the selling price.
A common mistake is looking only at the product cost and forgetting the fixed fee, which hits low-priced items hardest. Another is treating the platform percentage as the only fee when shipping is charged per order. Entering costs per single sale, rather than per batch, keeps the result accurate.
Frequently asked questions
How do I calculate profit per sale after fees?
Subtract the platform fee, fixed fee, product cost and shipping cost from the selling price. The remainder is your net profit per sale. Divide it by the selling price to get the real margin.
What is real margin?
Real margin is your net profit per sale divided by the selling price, shown as a percentage. Unlike a simple markup, it accounts for every fee and cost attached to the order.
Why does the fixed fee matter on cheap items?
A fixed fee is charged per order regardless of price, so it takes a larger share of a low selling price. On small-ticket items it can turn an apparent profit into a loss.
Does the calculator include taxes?
No. It covers platform fees, fixed fees, product cost and shipping only. If taxes apply to your sales, subtract them separately to see your final figure.
Are the results financial advice?
No. This is an educational tool and the results are estimates based on the values you enter. Use them as a starting point for your own cost review.
Free educational tool made with the help of AI and tested automatically on desktop and mobile. Results are estimates. Not financial advice.
