Construction & home

Home improvement and jobsite math in one place: room square footage, paint gallons from wall area, concrete cubic yards for slabs, roof pitch angle from rise and run, floor tile counts with grout waste, and mulch or gravel volume for beds and driveways. For dedicated garden bed, spacing, and rainwater tools see our gardening calculators hub. Handy for DIY quotes and contractor sanity checks — estimates only, not substitutes for on-site measurement.

Material estimates almost always need a waste allowance on top of the bare quantity. Tile and flooring typically get 10% extra for cuts, more on diagonal layouts or in rooms with many corners; paint coverage drops sharply on unprimed drywall or when going light over dark, so a second coat is the norm rather than the exception. Concrete is ordered in fixed increments, so round up and confirm the pour volume with your supplier. Measure each room individually rather than assuming rectangles — older houses are rarely square, and a small error in one dimension multiplies across an area calculation.