Density Converter
Convert kg/m³, g/cm³, lb/ft³, and other density units.
Unit
Density Converter
Generated on April 24, 2026
?What is the Density Converter?
A density converter moves between the common units of mass per unit volume: kg/m³ (SI), g/cm³ or g/mL (chemistry and compact materials), lb/ft³ (US construction), and lb/gal (US petroleum and liquids). Density is a fundamental property of every material — it controls whether something floats or sinks, how heavy a structure will be, and how concentrated a liquid is. Water is the easy reference point: pure water has density 1.00 g/cm³ at 4 °C, which equals exactly 1,000 kg/m³.
The Formula
Density is mass divided by volume (ρ = m / V). The SI unit is kilogram per cubic meter, but g/cm³ is equally popular because water's density is a convenient 1.00 g/cm³ — values above 1 sink, below 1 float. Because 1 g = 0.001 kg and 1 cm³ = 10⁻⁶ m³, the two units differ by exactly a factor of 1,000. Imperial units (lb/ft³, lb/gal) are legacy conventions in US construction and petroleum.
Practical Examples
Pure water at 4 °C has a density of exactly 1.00 g/cm³ or 1,000 kg/m³ — the reference baseline for all other materials.
Steel has a density of about 7.85 g/cm³ — 7.85 times heavier than the same volume of water.
Aluminum is 2.70 g/cm³, roughly one-third the density of steel — the reason it is preferred where weight matters.
Gold is 19.3 g/cm³, almost 2.5 times denser than steel — which is why a gold bar feels 'impossibly' heavy.
Human body density is close to 1 g/cm³ — which is why we float when the lungs are full and sink when we exhale.
Air at sea level has density 1.225 kg/m³ — about 1/800 the density of water.