ProjectMetrica calculators are designed as transparent planning tools. This page explains how we handle formulas, defaults, units, costs and uncertainty.
1. Formulas first
Material calculators start from measurable project dimensions and established unit conversions. The formula used by each tool is shown on the calculator page so the result can be checked independently.
2. Editable assumptions
Waste percentages, density, bag size, pallet coverage, compaction and local prices are not universal constants. When an assumption varies by supplier or project, we make it editable wherever practical.
3. Ordering units
Results are converted into units people actually use when buying materials, such as cubic yards, tons, bags, rolls, pallets, blocks or fence sections. Rounded ordering quantities are planning aids; supplier packaging and minimum order rules still apply.
4. Cost estimates
Cost calculators use the prices entered in the tool or clearly labeled planning defaults. They are not contractor bids and they do not include every possible permit, delivery, tax, demolition or site-specific cost unless the calculator explicitly provides an input for it.
5. Safety and professional requirements
Quantity math cannot determine whether a project is structurally safe or code-compliant. Retaining walls, grading, drainage, electrical work and other projects can require permits, engineering or licensed professionals depending on the location and scope.
6. Corrections
We review calculation logic when issues are reported. If you spot a formula or wording problem, contact us with the calculator name and example inputs so it can be reproduced.