Free BTU calculator for heating and cooling: size a furnace or AC from floor area, ceiling height, insulation and climate, rules shown in the open.
Home Project Calculators
Every calculator here is free, works without a signup, and never asks for your zip code or email before showing a result. Each one also shows its working on the page, the formula it uses, a worked example with real numbers, and the table of figures behind it, so you can check the maths instead of taking the tool’s word for it.
The calculators are companions to our cost guides: where a project has both, the calculator page links straight to the full guide, and the guide’s prices and the calculator’s are built from the same figures, checked on the same dates.
Free flooring calculator: boxes needed from room size, box coverage and wastage. Formula, worked example and rounding explained on the page.
Free roof pitch calculator: pitch, angle and slope multiplier, plus your true roof area from the footprint. Formula and multiplier table included.
Free tile calculator: tiles needed = area × (1 + wastage) ÷ tile area. Enter area and tile size; worked example and coverage table included.
Free tree removal cost estimator: price a removal by height, trunk size, access and stump grinding, with published location data, no zip or email asked.