Reseller ROI: How to Calculate Profit on Every Flip
Updated November 2026
ROI = net profit ÷ what you paid for the item. It answers "how hard did my money work?", which matters more to resellers than margin.
Example: a $6.99 thrift hoodie sold on Poshmark for $38
- Poshmark fee: 20% × $38 = $7.60 (buyer pays shipping)
- Supplies: $0.50
- Net profit: 38 − 6.99 − 7.60 − 0.50 = $22.91
- ROI: 22.91 ÷ 6.99 = 328%
Add time to the picture
A 300% ROI item that sits for 9 months ties up your cash and shelf space. Track days to sell and review anything unsold after 90 days: drop the price, cross-list, or bundle it.
Track the boring costs
- Shipping you pay (Mercari, eBay, Depop) vs buyer-paid labels (Poshmark)
- Poly mailers, tape and printer labels
- Gas and sourcing trips, at least as a monthly total
