Construction & Geometry · Glossary
What is Density?
Quick definition
Mass per unit volume, typically in kg/m³ or g/cm³. Different materials have characteristic densities.
Full explanation
Density is mass per unit volume (ρ = m/V). Common units: kg/m³ (SI), g/cm³ (CGS), lb/ft³ (imperial). Water has a density of 1,000 kg/m³ (1 g/cm³) at 4°C — the original metric reference. Steel ~7,850 kg/m³, air ~1.225 kg/m³, gold 19,300 kg/m³. Density determines whether something floats: less dense than the fluid = floats. Density changes with temperature (warm air rises) and pressure. In construction, density affects structural loads and material selection. In chemistry, density helps identify substances. Density is distinct from weight: weight depends on gravity, density is intrinsic to the material.
Related calculators
Calculators that use or explain Density.
Related terms
More from Construction & Geometry
Area
The amount of 2D space inside a shape, measured in square units (m², ft², acres, hectares).
Volume
The amount of 3D space inside a shape, measured in cubic units (m³, ft³) or in liters/gallons.
Perimeter
The total distance around the outside of a 2D shape. Measured in linear units (m, ft).
Circumference
The perimeter of a circle — the total distance around it. C = 2πr, or C = πd.
Slope
The steepness of a line, calculated as rise over run. Slope = (y₂ - y₁) / (x₂ - x₁).
Last reviewed: June 15, 2026 • Category: Construction & Geometry