SI-core dimensional arithmetic
Density, Mass and Volume
Solve ρ=m/V using metric or international-foot/avoirdupois-pound inputs. Optional geometric volume uses dimensions in millimetres or inches and is converted through one SI calculation core.
Physical result
ที่ BIPM SI Brochure, ninth edition updated in 2026 identifies kg/m³ as the coherent SI unit of mass density. NIST defines density as mass per unit volume and notes that a substance density is normally stated with conditions.
NIST SP 811 conversion guidance uses the international foot 1 ft=0.3048 m exactly and avoirdupois pound 1 lb=0.45359237 kg exactly. Therefore 1 ft³=0.028316846592 m³ and 1 lb/ft³=16.01846337396 kg/m³. Shape equations are general geometric identities, not ISO formulas.
Removed claims: the former material table was unsourced and internally inconsistent (PTFE appeared as both 1300 and 2200 kg/m³). The water-buoyancy/floating decision used full object volume even for partial immersion and has been removed. Kilograms, pounds and tonnes are mass units—not weight-force units.
