HelloProfit uses a standard formula for calculating gross ROI.
ROI = (Gross Sales - Expenses) / Cost;
Gross Sales: Total gross revenue received from the customer. (Gross Sales + Tax)
Expenses: FBA Fees, Referral Fees, Promos, Product Cost, Shipping Cost, Return Product Credits, Withheld Tax, Refunds and finally Advertisement Costs.
Cost: Product Cost, Shipping Cost, Return Product Credits, Advertisement Costs and Tax (If applicable).