Ecom Calc Tools offers a large set of free online calculators for ecommerce sellers, marketers, and SaaS founders. It covers fees, profit margins, ROI, ROAS, CAC, CLV, churn, MRR, burn rate, taxes, and payment costs across platforms like Amazon, eBay, Etsy, Shopify, TikTok Shop, Stripe, and PayPal. Everything runs in the browser, so there’s no signup, no email wall, and no data stored. The site also includes fee guides and comparison tools that help users understand platform costs and make better business decisions. It’s built for quick checks, side-by-side comparisons, and practical day-to-day planning.