Calculation Methodology

Transparent formulas and limitations for every Gravelwise estimate.

Area and volume

Rectangle area = length × width. Circle area = π × (diameter ÷ 2)². Custom outlines use the shoelace polygon formula, closing the last corner to the first. Crossing outlines and zero-area shapes are rejected. Curves are approximated by straight segments; no survey accuracy is implied.

In US mode: cubic yards = area in ft² × depth in inches ÷ 12 ÷ 27. In metric mode: cubic meters = area in m² × depth in centimeters ÷ 100. Convert m³ to yd³ by dividing by 0.764554857984.

Allowance and weight

Order volume = measured volume × (1 + allowance ÷ 100). US tons = order yd³ × entered bulk density. Densities are approximate editable planning presets, not laboratory measurements or supplier specifications. Allowance is not an engineered compaction conversion.

Prices and rounding

Rates per ton and yard multiply unrounded quantities. Bag count is total pounds divided by entered bag pounds, rounded up; bag pricing uses that whole-bag count. Total project quotes stay fixed when quantities change. Delivery and tax amounts are entered by the user. There is no live supplier price feed. Display rounding does not change intermediate calculation precision.

Layers and exclusions

Each layer uses the shared footprint and its own depth, density and allowance. Optional layer rates are per US ton. Sum weight and volume for logistics only; do not substitute one layer material for another. Unpriced layers are excluded from the priced subtotal.

Editorial transparency

Gravelwise content was developed with AI assistance and checked for consistency with the published formulas and linked educational resources. It has not been reviewed or endorsed by an engineer, contractor, quarry or university. Sources support general material principles, not the preset density values. Updated October 24, 2026.