A practical workflow
Follow the guide step by step
- 01
Estimate per-unit profit
Subtract supplier cost and applicable marketplace, fulfillment, inbound, advertising, discount, and return-related costs from expected selling proceeds.
- 02
Define the cash invested
Use a consistent unit-level cost basis that reflects the capital you commit to acquire and prepare the product. Document which costs are included.
- 03
Divide estimated profit by invested cost
Express the result as a percentage so different opportunities can be compared on the same basis.
- 04
Compare ROI with time and risk
A high unit ROI alone does not reveal how quickly inventory may sell, how much stock you must buy, or how long cash stays tied up.
- 05
Stress-test the assumptions
Recheck the result at a lower selling price and with plausible changes to fees, returns, and advertising.
Keep ROI separate from margin
ROI is estimated profit relative to invested cost. Profit margin is estimated profit relative to selling revenue. Both are useful, but they answer different questions.
Margin Seller displays both measures so sellers can examine unit economics from more than one angle. The result remains an estimate, not a promise of realized performance.
ROI vs margin: which to use
ROI measures profit against what you paid, so it guides how efficiently your cash works. Margin measures profit against the selling price.
Use ROI to compare deals when cash is limited, and margin to judge how much pricing pressure a product can absorb.
Example: ROI depends on the cash basis you choose
Illustrative example only: if a unit requires $20 of invested cash and your entered costs leave an estimated $5 profit, unit ROI is $5 ÷ $20 = 25%. If the same estimated $5 profit requires $25 of invested cash, ROI is 20%. The arithmetic is useful only when you define which costs are included in invested cash.
Unit ROI does not describe how quickly the unit may sell. A product with the same calculated ROI can tie up cash for a different number of months, or require a much larger minimum order. Review months of cover and total order cash separately.
- Use profit after the costs in your model as the numerator.
- State whether inbound, preparation, and other committed costs are included in invested cash.
- Compare ROI alongside margin, order size, and expected inventory hold—not by itself.
Common questions
Frequently asked questions
Can a product have a high margin but low ROI?
Yes. Margin and ROI use different denominators, so the same estimated profit can produce different percentages.
Should ROI include marketplace fees?
Estimate profit after applicable fees first, then compare that profit with a clearly defined amount of invested cash.
What is a good ROI for resellers?
It depends on your capital and risk. Many resellers want a minimum percentage and a minimum dollar profit, because a high percentage on a very cheap item may not be worth the effort.
Ready to check a listing?
Put the assumptions to work.
Bring the visible listing facts and your own costs into a product audit before you commit to inventory.