I built ProjectCalc — a free library of 73 calculators for construction, home improvement, and DIY projects. No signup, no popups, no AI chatbot, runs entirely in your browser. Stack: Next.js 16 (App Router) + TypeScript + vanilla CSS, deployed on Vercel. Source: github.com/sabanite08/projectcalc ## Why Every existing construction calculator on Google is buried under cookie banners, popup signups, AI chatbots, and ads. The Reddit answer to "how much concrete do I need" is always a screenshot from someone else's calculator because the original site is unusable. So I built the version I wanted: dead simple, fast, no friction.…