How to calculate resale margin (platform fees, shipping and ads included)

Most new resellers overestimate profit because they compare the sale price with the item cost and stop there. Real profit has many more lines. Here is how to calculate it properly.

The full profit formula

Profit = sale price + shipping charged to buyer − platform selling fee − payment processing − fixed per-order fees − ad/promoted listing fees − item cost − inbound shipping and import taxes − your outbound postage − packaging − an allowance for returns.

Platform fees (approximate — always check the current fee page)

• eBay: a final value fee of roughly 13–15% for most categories, charged on the total including shipping, plus a small per-order fee (about $0.30–$0.40). Promoted listings add a percentage you choose.
• Etsy: a $0.20 listing fee, a 6.5% transaction fee (including shipping) and payment processing of about 3% + $0.25 in the US; offsite ads can add 12–15% on some sales.
• Poshmark: a flat $2.95 for sales under $15 and 20% at $15 and above.
• Mercari (US): a selling fee of around 10% plus payment processing of about 2.9% + $0.50.
• Facebook Marketplace: local pickup is free; shipped sales carry a selling fee (around 10%, with a minimum).
• TikTok Shop: a referral fee on each order that varies by category and region; affiliate creator commissions are extra.

Fees change regularly and differ by country and category, which is why every preset in our calculator is editable.

Margin vs ROI vs break-even

• Margin = profit ÷ revenue. A 30% margin means you keep $0.30 of every dollar the buyer pays.
• ROI = profit ÷ total cost. A $4 item that nets $6 profit after everything has 150% ROI — great on paper, but small in absolute dollars.
• Break-even price is where profit is zero. If similar items regularly sell below your break-even, skip the product.

Worked example

You sell a phone stand for $14.99 with free shipping on eBay. Item cost $3.20, inbound shipping $0.80, postage $4.10, packaging $0.30. Fees at ~13.6% + $0.40 ≈ $2.44. Profit ≈ 14.99 − 2.44 − 3.20 − 0.80 − 4.10 − 0.30 = $4.15: a 28% margin and 49% ROI. Notice that postage costs more than the item — for cheap products, shipping is usually the biggest cost.

Costs people forget

• Import VAT/duties and customs handling fees.
• Returns, damaged units and “item not as described” refunds — budget a few percent.
• Unsold stock and samples that never sell.
• Your time for photos, listing, packing and trips to the post office.
• Income tax on profit.

Plug your own numbers into the resale profit calculator.

General information only, not tax or financial advice. We may earn a commission from qualifying purchases.