Fees used in this calculator
eBay: 13.6% of the total sale (item plus shipping) for most categories, plus $0.40 per order ($0.30 on orders of $10 or less). Some categories, such as books and media or high-value items, use different rates.
Poshmark (US): a flat $2.95 on sales under $15 and 20% on sales of $15 or more. The fee covers payment processing, and buyers pay for the shipping label.
Return vs margin
Return on what you paid tells you how hard your money worked: a $2 item that nets $20 profit is a 1,000% return. Margin tells you how much of each sale you keep. Resellers usually care about both.
The formulas behind it
Every result cell is a plain spreadsheet formula, so you can check the math or rebuild it yourself.
| Cell | Result | Formula |
|---|---|---|
| B10 | Sale total | =B3+B4 |
| B11 | Platform fee | =IF(eBay, B10*13.6%+0.40, IF(Poshmark, IF(B3<15, 2.95, B3*20%), B10*B7%)) |
| B12 | Your costs | =B5+B6 |
| B13 | Profit | =B10-B11-B12 |
| B14 | Return on what you paid | =B13/B5 |
| B15 | Profit margin | =B13/B10 |
Sources
Rates checked September 2026. Platforms change fees from time to time.