Clear numbers. Transparent assumptions.

FeeMargin helps freelancers and online sellers understand the difference between a headline price and the money they keep. We are independent of the platforms listed. Our calculators and 192 scenario guides use the same calculation engine, with editable assumptions and visible deductions.

Published rates, with the assumptions exposed

Defaults model US-dollar transactions and illustrative US schedules. Standard published card-not-present pricing means a customer pays remotely, such as through an online checkout. It is distinct from in-person terminals, manually entered cards, negotiated volume pricing, bank transfers and premium payment products. Country, currency, card origin and account terms can all change the rate.

Stripe’s standard US online domestic-card assumption is 2.9% plus $0.30. The percentage applies to the gross payment; the fixed charge applies per transaction. International-card and currency-conversion costs are separate. A processor’s published headline rate is a starting point, not a quote for your account.

Marketplace referral and processing rules

A marketplace can charge a referral or transaction percentage, a separate processing percentage and fixed charge, listing fees, and advertising fees. We show these separately. In our simplified e-commerce model, the fee base is item price plus shipping collected. Etsy’s transaction-rate assumption is 6.5%; processing is modeled separately using a US schedule.

Actual fee bases may include tax, delivery or gift wrapping, and may depend on category, minimums, caps, subscription tier or account country. Amazon fulfillment charges require your own allocation. eBay category tiers and tax-inclusive bases are not automatically inferred. Etsy offsite-ad caps are not modeled. Use the overrides and cost fields to reflect your own schedule.

Forward payout and reverse-invoice algebra

For gross invoice G, percentage rate r expressed as a decimal, and fixed charge f, the basic payout is N = G × (1 − r) − f. Solving for an invoice that delivers target N gives:

G = (N + f) / (1 − r)

Adding the percentage to your target is insufficient because the fee also applies to the extra amount. At 2.9% + $0.30, the algebraic gross needed for $1,000 net is approximately $1,030.175. The implemented calculator searches cent-denominated invoices using its individually rounded fee components and minimum-fee rules, rather than relying only on the unrounded formula. Rates totaling 100% or more cannot produce a finite positive target payout.

Profit, margin and break-even

Revenue is sale price plus customer shipping. Net profit deducts platform, processing, listing, regulatory and advertising fees, product costs, and shipping or allocated overhead. Margin is net profit divided by revenue. Return on cost divides profit by product and fulfillment costs; zero investment produces an undefined ROI. Break-even solves the linear cost model before cent rounding, so allow a rounding buffer.

FX is an entered markup on gross receipts, not a live exchange rate. Providers converting the balance after fees may settle differently. Income taxes, refunds, disputes, subscriptions, reserves and payout timing are excluded unless you explicitly allocate a cost. Results are planning estimates.

Rate audit: October 2026

Last editorial audit: October 28, 2026. The source review covered Stripe’s US domestic online-card headline rate, Etsy’s transaction rule, and Upwork’s variable 0–15% contract fee range. Upwork’s 10% preset is an example; use the fee quoted on your contract. This is a scoped source audit, not a claim that every account-specific rate was verified. Other presets remain disclosed planning assumptions requiring confirmation.

Corrections and editorial independence

We prioritize official pricing and help pages over third-party summaries. When a fee changes, the preset and generated scenarios should be updated together. Advertising does not change formulas or comparison rankings. Report a discrepancy with the official source, effective date and applicable country or plan.