Our methodology, data sources, and verification process
Our calculator determines seller profits by computing all applicable marketplace fees for a given sale price, then subtracting those fees along with the seller's costs (item cost and shipping expenses) from the total transaction amount. We account for the full fee stack of each marketplace, including selling commissions, payment processing charges, listing fees, and platform-specific adjustments.
Below we detail how we source our fee data, which variables we track for each marketplace, our calculation approach, and how we keep everything current.
We start with each marketplace's official seller documentation, help center articles, and fee schedule pages. These are the primary authority for current fee rates.
Each marketplace has a unique fee formula. We model every component: percentage-based commissions, fixed per-transaction fees, tiered rates based on seller level or category, and conditional fees like offsite advertising or international surcharges.
Fee formulas are implemented in code with precise rounding behavior matching each marketplace. We test calculations against known sale scenarios and real seller payouts to verify accuracy.
We monitor marketplace announcements and fee policy changes. When a platform updates its fee structure, we revise our calculations and note the update date on the relevant marketplace page.
At its core, every marketplace calculation follows this structure:
1. Total Sale Amount = Sale Price + Shipping Charged to Buyer
2. Selling Fee = Total Sale Amount x Marketplace Commission Rate
3. Payment Processing = Total Sale Amount x Processing Rate + Fixed Fee
4. Total Fees = Selling Fee + Payment Processing + Additional Fees
5. Total Costs = Item Cost + Shipping Cost
6. Final Profit = Total Sale Amount - Total Fees - Total Costs
"Additional Fees" varies by marketplace and may include listing fees (Etsy), international surcharges (eBay), offsite advertising fees (Etsy), referral fees (Amazon, Walmart), seller level adjustments (StockX, GOAT), or VAT (Viagogo).
We offer three calculation modes, each using the same underlying fee engine:
Enter your sale price and costs. We compute all fees and show your net profit. This is a direct, forward calculation.
Enter your desired profit and costs. We use a binary search algorithm to find the sale price that yields your target profit after all fees. The algorithm converges within 80 iterations to a precision of $0.01.
Enter your costs only. We find the minimum sale price where you don't lose money -- the point where revenue exactly covers all fees plus your costs. This uses the same binary search approach with a target profit of zero.
Below is a summary of the primary data sources and key variables we track for marketplaces available in United States:
| Marketplace | Primary Source | Key Variables |
|---|---|---|
| eBay | eBay Seller Center fee schedule | Category, store plan, seller level, international, promoted listings |
| Mercari | Mercari seller fee page | Flat 10% + payment processing |
| Depop | Depop seller terms | No seller fees (buyer-fee model) |
| Poshmark | Poshmark fee page | Tiered: flat fee under $15, 20% above |
| Grailed | Grailed seller FAQ | 8% commission + payment processing |
| StockX | StockX seller guide | Seller level (1-5), payment processing |
| GOAT | GOAT seller FAQ | Seller rating tiers (below 50 to 90+) |
| Facebook Marketplace | Meta Commerce policies | 5% shipped, $0.40 minimum |
| OfferUp | OfferUp seller terms | 12.9%, $1.99 minimum |
| Etsy | Etsy fee policy page | Listing fee, transaction fee, payment, offsite ads, currency conversion |
| Amazon | Amazon Seller Central fee schedule | Category referral fee, seller plan, per-item fee |
| Walmart | Walmart Marketplace seller help | Category-based referral fee |
| Ticketmaster | Ticketmaster seller policies | Commission range, event/venue variation |
| StubHub | StubHub seller FAQ | Commission range, event/venue variation |
| SeatGeek | SeatGeek seller terms | Commission range, event/venue variation |
| AXS | AXS resale policies | Commission range, event/venue variation |
| TickPick | TickPick seller FAQ | Commission range, event/venue variation |
| Gametime | Gametime seller terms | Commission range, event/venue variation |
| Vivid Seats | Vivid Seats seller policies | Commission range, event/venue variation |
| Razorgator | Razorgator seller terms | Commission range, event/venue variation |
| TicketCity | TicketCity seller FAQ | Commission range, event/venue variation |
| Viagogo | Viagogo seller policies | Commission range, VAT (regional) |
We support fee calculations across 8 regions: United States, United Kingdom, Canada, Australia, European Union, Japan, India, and Brazil. Regional differences we account for include:
We review and verify fee data on an ongoing basis. Each marketplace page displays a "Fees last verified" date showing when we last confirmed that marketplace's fee structure. Major fee changes are typically reflected within days of a marketplace's announcement. We conduct comprehensive audits of all marketplace fees at least quarterly.
While we strive for maximum accuracy, there are inherent limitations to any fee calculator:
If you notice a discrepancy between our calculations and your actual marketplace payouts, we want to know. Use the feedback button on any calculator page to report inaccuracies. We investigate every report and update our data accordingly.