Free calculators for real business decisions

Free fee and profit calculators for online businesses.

PenguinCalc collects practical calculators for PayPal fees, Stripe fees, eBay seller fees, Shopify profit, YouTube creator metrics, and payment platform comparisons. Fast answers, clear assumptions, no spreadsheet wrestling.

Calculator directory

Use the live tools below. Each calculator is published only after the formula, assumptions, and source notes are ready.

Built for useful answers, not generic widgets.

Each PenguinCalc tool is designed around the exact decision a seller, freelancer, or operator needs to make: how much they keep, what to charge, and which platform costs less.

  • Clear assumptions and official source links where fee data matters.
  • Reverse calculations for pricing invoices and offers without losing margin.
  • Only completed, working tools and focused tool hubs are shown on the homepage.