Paul Gunder
Paul Gunder builds calculators and reference tools at Rocky Mountain Apps, the company behind Reselling Math. He wrote each calculator on this site and checks every fee it uses against the marketplace's own fee pages. How that works is on the methodology page.
To report an error or ask about a result, email hello@resellingmath.com.
Written by Paul Gunder
Fee guides
- Does an eBay Store Pay for Itself?A break-even table for eBay's Store subscription tiers, built from the 13.6% versus 12.7% final value fee split and each tier's monthly price.
- Free Shipping or Buyer-Paid? What Happens to the FeeA per-platform table of what folding shipping into "free shipping" does to each marketplace's fee, and where Depop's label choice matters.
- Promoted and Boosted Listings, and What They CostWhat eBay Promoted Listings, Depop's 12% boost and Whatnot's high-value promotion actually charge, and what a paid promotion has to earn back.
- Which Platform to List On, by Item and PriceA decision procedure for choosing among eBay, Mercari, Poshmark, Whatnot and Depop, built from each platform's own category rates and fee thresholds.
- What Changed in Marketplace FeesA dated log of four marketplace fee changes this site's saved source pages evidence — Depop, Mercari, Poshmark and Whatnot — each with its effective date.
- What Each Marketplace Charges Fees OnA side-by-side table of what eBay, Mercari, Poshmark, Whatnot and Depop charge fees on — item price, shipping, tax and flat per-order fees.
- Whatnot's Seller Fee Tiers, ExplainedWhatnot's six-vertical, seven-tier commission table, its 28-day rolling window, the September 2026 rollout dates, and what this site doesn't model.
Calculators
- Depop Fee & Profit Calculator (2026)Work out Depop's payment processing fee and the 12% boosting fee on a US sale, and see your payout and profit after shipping and cost.
- eBay Fee & Profit Calculator (2026)Estimate eBay's final value fee, per-order fee and promoted listing cost by category and store level, then see your payout and profit.
- Mercari Fee & Profit Calculator (2026)See Mercari's 10% selling fee on your item and the shipping your buyer pays, then your payout and profit after the label and cost.
- Poshmark Fee & Profit Calculator (2026)Calculate Poshmark's fee (a flat $2.95 under $15, 20% from $15 up) and what you keep, including the cliff right at $15.
- Whatnot Fee & Profit Calculator (2026)Work out Whatnot's commission and payment processing fee on a sale, and what you keep after shipping and cost of goods.
- Where to Sell? Marketplace Fee Comparison (2026)Compare fees and profit for one item on eBay, Mercari, Poshmark, Whatnot and Depop side by side, ranked by what you keep.