Most payment fee calculators are clunky, loaded with ads, and run outdated rates. VendorCalcs is an ad-free, zero-latency payment fee auditor for founders, sellers & freelancers. What makes it stand out: • Reverse Invoice Gross-Up: Calculate the exact amount to bill to hit your net target • Refund Loss Audit: See how much unrefunded fees bleed your margins on returns • 19 platforms (Stripe, PayPal, Shopify, LemonSqueezy, Etsy) across 5 countries • Zero ads, no sign-ups, 100% free