Editorial Policy, Methodology & Sources

1. How each calculator is built

1. Define the job. We start from what a supplier sells (cubic yards, tons, bags, sheets, boxes, squares, gallons) and what the user can measure.
2. Use standard math. Volumes and areas use exact geometry. All dimensions are converted to feet internally (1 yd³ = 27 ft³; 1 in = 1/12 ft; 1 m = 3.28084 ft).
3. Apply published material values. Densities, bag yields, coverage rates, and code minimums come from the sources below. Where values vary by product or region, we use a typical figure, say so on the page, and make it editable.
4. Add waste explicitly. Waste and compaction factors are shown as their own input, never hidden inside a result.
5. Test. Each tool is checked against hand-worked examples, including the worked example printed on its page, before publishing.

2. Sources we rely on

• Building codes: International Code Council — International Residential Code (IRC), for minimums such as footing size, stair riser and tread dimensions, and guard heights. Local amendments always take precedence.
• Concrete and masonry: published bag yields from major U.S. premix manufacturers (for example, an 80 lb bag of concrete mix yields about 0.60 ft³), plus industry guidance from the American Concrete Institute (ACI) and the Portland Cement Association (PCA).
• Reinforcing steel: ASTM A615 / CRSI standard bar sizes and unit weights (for example, #4 bar = 0.668 lb/ft).
• Aggregates and soil: typical loose densities published by quarries and landscape suppliers (crushed stone is commonly about 1.4 tons per cubic yard). Densities vary with moisture and gradation, so they are always editable.
• Insulation and energy: U.S. Department of Energy / ENERGY STAR recommended R-values by climate zone.
• Lawn and seed: seeding rates published by U.S. university cooperative extension services.
• Product coverage: manufacturer data sheets for paint, grout, shingles, siding, flooring cartons, and coatings. Coverage varies by product, so these defaults are editable.

3. Prices

Cost fields use editable national ballpark prices to show the math. They are not quotes. Material and labor prices vary widely by region, season, and order size. Always enter your supplier's price for a real budget.

4. Content standards

• Every page states what the calculator assumes and when you should not rely on it (for example, structural design).
• We write for clarity: a quick answer first, then the formula, a worked example, reference tables, and FAQs.
• We do not publish fake reviews, testimonials, or credentials, and we do not let advertisers influence content.

5. Updates and corrections

Pages show a "last reviewed" date. When a reader reports an error, we verify it against the sources above, fix it, and update the date. Report a problem through the contact page with the page URL, your inputs, and the result you expected.

6. Limits of use

Calculators provide planning estimates. They do not replace a licensed engineer, architect, or your local building department. See the disclaimer and terms.

Last updated: October 8, 2026.