Sources we use
We rely on manufacturer product specifications and data sheets, university extension publications, government standards (such as NIST and USDA NRCS) and standard engineering references (such as US Army earthmoving tables and industry associations like CMHA and ACI). We do not use retailer blogs, forums or social media as sources of fact.
How calculators are checked
Every calculator uses published, standard formulas. The code is covered by automated tests that check known answers (for example, 27 cubic feet make one cubic yard, and a 10 × 10 ft area 3 inches deep is 0.926 cubic yards). We show the formula next to each tool so anyone can verify the result by hand.
What we will not publish
- Paid placements, supplier price lists or reviews written for a seller.
- Links to retailers or "where to buy" recommendations.
- Claims we cannot support with a source.
Updates and corrections
Each page shows the date it was last updated. When product specifications, extension guidance or standards change, we update the affected pages. If you find an error, tell us through the contact page and we will review it and correct it.