Profit calculator
Free, no sign-up, runs in your browser.
Profit per unit is the only number that decides whether a product is worth selling, and it is the one most spreadsheets get wrong — usually by forgetting a fee that is charged on the price rather than on the cost. This calculator itemises every fee the channel takes and subtracts every cost you pay, and shows the result alongside the margin, markup and ROI that describe it.
The formula
Profit = revenue kept − all fees − all costs. Revenue kept is the price minus any tax you are collecting on someone else's behalf, which was never yours.
A worked example
A $29.99 product that lands at $8.00, sold on Amazon FBA in Home & Kitchen, 10×6×3 inches and 20 ounces packed:
| Revenue kept | $29.99 |
|---|---|
| Total fees | $10.35 |
| Total costs | $10.00 |
| Profit per unit | $9.64 |
| Margin | 32.14% |
| Markup | 96.4% |
| ROI | 96.4% |
What to watch
- Inbound shipping to the warehouse is a cost per unit, not an overhead — divide the freight bill by the units in the shipment.
- Returns are a real cost on every unit sold, not an occasional surprise. Add your return rate times the unit cost under “other costs”.
- Advertising belongs in the per-unit cost too, at your actual spend divided by units sold rather than the spend on the units it converted.
- A monthly subscription is fixed, so its cost per unit depends entirely on volume — at 10 units a month Amazon's plan is $4 a unit, at 1000 it is four cents.
The trap
Counting tax as revenue. If you collect VAT, that money is not yours and never was; including it inflates every ratio below it and makes a thin product look healthy.
Questions
What should go under “other costs”?
Anything you pay per item that is not the product or its inbound freight: packaging, inserts, prep or labelling, your return allowance, and advertising divided by units sold. Leaving these out is the usual reason a calculated profit never shows up in the bank.
Does profit include the monthly subscription?
Only if you tick the box that spreads it over your monthly volume, which is the honest treatment: it is a real cost, but it is fixed, so it belongs divided by the units that actually carry it.
Why is my profit negative on a product that sells?
Usually a size tier. Check the dimensions are the packed box rather than the product, because fulfilment is billed on the greater of actual and dimensional weight and one extra inch can move you into the next tier.
Rates on this page are the published schedules as of 2025-01-15 and are applied by the same code the calculator runs. Marketplaces reprice — confirm against your own seller dashboard before setting a price.