Methodology & data sources

Every number on this site is computed, not guessed. Here is exactly how.

1. How much material you need

Quantities come from geometry and published material constants. For bulk materials we compute volume (area × depth), convert to the unit you buy in — cubic yards, tons, bags — using the material’s density or coverage rate, then add a waste allowance. For sheet, board, gallon and piece-based materials we divide the area or length by the coverage of one unit and round up. The exact constants are on the material reference page.

2. Waste allowances

We add a realistic waste factor so you do not run short: typically 5% for bulk aggregates and concrete, 10% for boards, sheets, pavers and rebar laps, and 10–15% for tile depending on layout. Each result shows both the exact requirement and the recommended amount to buy.

3. Material prices

Prices are national-average estimates for 2026 and are shown as a range, never a single false-precision figure. They are a planning aid, not a quote. Refresh them from local supplier pricing or the US Bureau of Labor Statistics Producer Price Index (series WPU13, construction materials) as markets move.

4. Regional installed-cost model

Installed-cost estimates combine national-average materials with a labor cost that is scaled by a per-state factor relative to the US average (1.00×). The factor approximates published state-level construction cost indices and construction-trade wage differentials from the BLS Occupational Employment and Wage Statistics. Material delivery is treated as partly regional. Every estimate is a range, and the state page shows how that state ranks against the other 51.

5. Limitations

These tools estimate typical residential jobs. They do not account for site access, demolition, permits, complex shapes, premium finishes, or your specific contractor’s pricing. Always confirm quantities with your supplier and get local quotes before buying or hiring.