For online sellers in USD
Seller Fee Kit
Estimate marketplace fees, payment costs, profit margins, and ad break-even points before a product, discount, or campaign goes live.
US / USD estimate
Stripe Fee Calculator
Estimate US online card processing fees.
Uses Stripe's listed US online card processing rate: 2.9% plus $0.30 per successful card charge.
Additional international card, currency conversion, dispute, tax, or account-specific fees may apply.
Core tools
Start with the calculators sellers use most often
Break-even ROAS Calculator
Calculate the ROAS, ACOS, and ad spend level where an order breaks even.
Profit mathDiscount Profit Margin Calculator
Estimate discounted sale price, remaining profit, and margin after a promotion.
Payment feesPayPal Fee Calculator
Estimate US PayPal Checkout fees, net amount, and effective fee rate for a transaction.
Profit mathShopify Profit Margin Calculator
Estimate Shopify order profit and margin after product costs, shipping costs, and payment fees.
Payment feesStripe Fee Calculator
Estimate US Stripe online card processing fees, net amount, and effective fee rate.
Transparent math
Every tool shows its assumptions
Seller Fee Kit is built around visible formulas, versioned rate assumptions, source links, and update notes. The first release focuses on US sellers and USD estimates.
Last updated: June 2026. Rates may vary by country, category, seller plan, account status, promotion, and payment method. Estimates are not financial, tax, or legal advice.