Measured volume and separate extra material
Version 1.0.0 sums non-overlapping rectangular areas and their entered depths: area_ft² = length_ft × width_ft; volume_ft³ = Σ(area_ft² × depth_ft). One cubic yard contains 27 ft³. Unit normalization follows the bulk-volume method, using NIST SP 811.
Adjusted volume = measured volume × (1 + extra percentage / 100). Extra is explicitly entered from 0–100%, with zero as the initial value. It is not a compaction factor. Driveway, shed, patio, walkway and fill contexts never set a construction depth or density.
Density converts volume into an estimate
Estimated weight_lb = adjusted volume_ft³ × entered density_lb/ft³. Estimated short tons = weight_lb ÷ 2,000. If the supplier states short tons per cubic yard, normalized density_lb/ft³ = entered tons/yd³ × 2,000 ÷ 27. Only US short tons are supported; metric tonnes and long tons are different units.
The density is required, editable and initially blank, with a material name and source/state note. No presets are supplied. Changing density units clears its value to prevent reinterpreting a pounds-per-foot value as tons-per-yard. The entered value must be positive and finite, at most 1,000 lb/ft³ or 20 short tons/yd³; these are input-error bounds, not endorsed gravel ranges. Up to 30 positive rectangular sections are supported.
For a supplied density in short tons/yd³, substituting density_lb/ft³ = density_tons/yd³ × 2,000 ÷ 27 into the weight equation gives estimated short tons = adjusted yd³ × density_tons/yd³. The two density input bases therefore describe the same conversion when their values match. Neither input basis establishes the material state or a supplier density. Results round for display to four decimal places; intermediate and canonical measurements do not. No purchase line or weigh-ticket precision is claimed.
Compacted reference ranges are not delivery densities
FHWA NHI-05-037 Table 5-17 reports typical compacted dry unit-weight reference ranges for gravel/sand classifications: GW approximately 125–134 lb/ft³; GP 115–125; GM 119–134; GC 115–125. These geotechnical ranges describe classification and state; they are not exact loose-delivery densities or selectable supplier presets.
FHWA-RD-97-148, Granular Base application description discusses gradation, particle shape, fines, drainage, stability and compaction. These influences are why a single universal gravel density would imply false precision. Do not multiply a finished compacted volume by loose density without reconciling the material state with the supplier.
Follow the gravel measurement guide and yards-versus-tons decision. Supplier increments, minimums and fees belong in Aggregate Ordering, where an already-added allowance must not be added again.