50+ free calculators for concrete, roofing, framing, lumber, electrical, and landscaping. Built for contractors and DIY homeowners who need fast, accurate material estimates. Every calculator includes verified 2025–2026 US pricing, waste factor options, imperial and metric units, and plain-English result explanations — not just a number. No signup. No ads. Works on any device. All calculators can be embedded on any website for free via iframe.