Track the whole resale business.
Unhinged Reseller Desk keeps inventory, sales, returns, business expenses, pricing and actual profit together in one local-first toolkit.
See the full Reseller Desk — $79How to calculate reseller profit
Start with the amount the buyer pays, then subtract every cost required to create and complete that sale. That normally includes what you paid for the item, marketplace or payment-processing fees, shipping you cover, packaging supplies and any other sale-specific costs. What remains is the estimated net profit from that sale before taxes and broader business overhead.
For example, a $50 sale is not a $50 profit. If the item cost $10, fees total $6.80, shipping costs $5 and packaging costs $0.50, the money left is much smaller than the headline sale amount. That is why tracking revenue alone can make a resale business look healthier than it really is.
Use the actual fee percentage or fixed fee you expect for the marketplace and category you are selling in. If you offer free shipping, include the postage you pay. If the buyer pays shipping separately and that money exactly covers your label, avoid counting the same shipping cost twice. Recalculate when fees, shipping rates or your own costs change.