How our estimates work
Our calculators turn your measurements into practical quantities using visible formulas and clearly labeled assumptions.
Measurements and units
The MVP accepts U.S. customary measurements. Lengths are converted to feet before area and volume calculations. Area is calculated in square feet, volume in cubic feet, and bulk volume in cubic yards using exactly 27 cubic feet per cubic yard. Weight and liquid conversions are used only where the individual calculator calls for them.
Full precision, readable results
Calculations retain normal JavaScript numeric precision internally. We round only for display, choosing a small number of decimal places that is useful for purchasing. Whole-bag estimates and whole 1-gallon container equivalents round upward because partial packages may not be purchasable. This avoids showing misleading fake precision.
Calculated amount and purchase estimate
A calculated amount follows the displayed formula using the measurements and product or project values entered. When selected, a waste, buffer, or extra percentage is applied separately:
Purchase estimate = calculated amount × (1 + selected allowance ÷ 100)
A default allowance is a planning convenience, not a universal rule. You can change it, including setting it to zero.
Variable assumptions
Some mathematically calculated outputs still depend on values that are not universal. Examples include gravel density, grass-seed application rate, mulch or topsoil bag volume, concrete bag yield, sod supplier coverage, paint coverage and planned coats, paver base or bedding depth, and deck board face width, gap, or stock length. Product, manufacturer, supplier, and applicable project values should be verified before purchase.
Three levels of estimate accuracy
We separate exact math from variable inputs: geometry and unit conversions are calculated directly, supplier-, manufacturer-, product-, or project-specific values come from the applicable source, and editable percentages remain user-selected planning allowances. In short: exact math → supplier/product-specific values → user-selected planning allowances.
Why the real amount may differ
Calculator results are planning estimates, not quotes or guarantees. Measurement error, irregular shapes, slope, grade, compaction, settlement, moisture, spills, surface texture, application method, site conditions, and product variation can all affect material use. A calculator is not a site inspection, engineering design, code review, or professional recommendation.