Free, fast trade calculators — no signup, imperial and metric, built to match the building codes that actually apply on site. Each tool explains its math and prints a clean layout sheet you can take to the job.
Every tool here follows the same rules: the formula is shown and sourced, code limits (IRC in the US, OBC in Ontario) are checked automatically with plain-language warnings, results work in both unit systems, and a print button produces a one-page layout sheet with your numbers. Where a calculation feeds a project decision, the tool links straight to real cost data for that work in your city.
More calculators are added as they meet that bar — roofing, lumber, drywall and concrete tools are in the build queue.