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Marketplace Fee-Aware Promotion Calculator

Marketplace referral fees, fulfillment fees and per-order ad spend all come out before you see a dollar of profit. This calculator factors in all three before evaluating a promotion.

e.g. Amazon category referral fee, Etsy transaction fee.

e.g. FBA pick/pack/ship fee.

Sponsored ad cost attributed to this listing per order.

Promotion

Contribution profit per order (with promotion)
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Profit without promotion
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Margin with promotion
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Total marketplace costs/order
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Volume uplift needed
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Referral fees are typically charged as a percentage of the sale price actually paid by the customer (post-discount), which this calculator applies automatically. Fulfillment fees and ad spend are treated as flat per-order costs that don't change with the promotion.

How it works

Formulas used

Payment/referral fee = Sale price × Referral fee% Contribution profit = Sale price − Product cost − Referral fee − Fulfillment fee − Ad spend

Worked example

$30 price, $8 cost, 15% referral fee, $4.50 fulfillment fee, $2 ad spend, 20% off promotion:

Marketplace fees compress promotional margin far more than a direct-to-consumer discount of the same headline size — always model them explicitly rather than assuming your normal margin cushion applies.

Related calculators

Promotion Profit Calculator
The general comparison engine, with optional fee fields.
Discount Profit Calculator
A simpler direct-to-consumer version of this analysis.

Frequently asked questions

Do referral fees apply before or after a discount?

Most marketplaces charge referral/commission fees on the actual sale price the customer pays — this calculator applies the fee after the discount, which is the more common (and more conservative) assumption.

Should I include ad spend in every promotion evaluation?

If you run sponsored ads on the listing being promoted, yes — otherwise a promotion can look profitable in isolation while still losing money once acquisition cost is included.

Model the marketplace settlement, not just the sale price

Marketplaces can charge percentage fees, fixed order fees, fulfillment charges and ad costs on the same order. A promotion should be evaluated against the amount you actually retain after every variable deduction.

Reconcile the scenario

  • Use the fee rate from a recent settlement report for the exact category and program.
  • Include promoted-listing or marketplace ad spend when it scales with the sale.
  • Compare the offer with direct-channel economics before shifting inventory.

Marketplace variables

  • Fees may apply to shipping and tax as well as merchandise revenue.
  • Fulfillment and storage charges can change by size, season and inventory age.
  • Platform-funded discounts should be separated from seller-funded discounts.