1. Selling and transaction fees
Check the category-specific commission, transaction fee, listing or insertion fee, per-order charge, and any minimum or maximum fee. Confirm whether shipping charged to the buyer is included in the fee base.
2. Payment processing
Record both the percentage and fixed per-transaction component. Check how refunds, partial refunds, currency conversion and international cards are treated under your payment provider's policy.
3. Fulfilment and shipping
Include postage, pick-and-pack, packaging, labels, inbound freight, prep, storage, long-term storage and removal or disposal charges where relevant. Allocate shared shipments consistently across units.
4. Advertising and promotions
Track promoted listing rates, offsite advertising charges, coupons, discounts, affiliate commissions and paid traffic. Separate the discount given to the customer from the advertising fee charged to the seller.
5. Returns and operational leakage
Estimate return postage, unrecoverable fees, damaged stock, replacements, chargebacks and customer-service concessions using actual historical data where possible.
Keep assumptions current
Marketplace fee schedules change and can vary by country, category, seller plan and account eligibility. Use the platform's official fee documentation and your own statements as the source of truth. The Margenao calculators are editable estimates, not official fee quotes.
A repeatable fee-audit workflow
- Export a recent period of order-level transactions and the separate fee or settlement report.
- Choose several representative orders, including one with a discount, one with buyer-paid shipping and one with a refund or partial refund.
- For each order, identify the fee base, percentage rate, fixed charge, category or plan tier, and any separately billed listing or subscription fee.
- Compare the calculated estimate with the actual fee posting. Record the difference and the platform transaction reference.
- Update your calculator assumptions only after confirming the current policy and fee schedule for your country, category and account.
Example: why one percentage is not always enough
Suppose a simplified estimate applies a 12% fee to $50 of eligible proceeds, producing $6. An actual statement may show a separate fixed order charge, a different fee base that includes shipping, a category-specific rate or an adjustment posted later. The difference is not necessarily an error in the estimate; it may reflect a fee rule the simplified model does not represent. Keep the actual statement as the source of truth.
Keep a dated assumptions log
For each channel, record the country, category, seller plan, fee name, percentage or fixed amount, effective date, official source and date checked. This makes it easier to explain why a historical order differs from a current calculator estimate.