Convert density between kg/m³, g/cm³, lb/ft³, and more. Includes specific gravity, floatation check, and a 20-material reference table.
The density converter accepts a value in any of 10 density units — kg/m³, g/cm³, g/mL, kg/L, lb/ft³, lb/in³, lb/gal, oz/in³, kg/cm³, and t/m³ — and instantly converts to every other unit plus specific gravity.
Preset buttons load densities of common materials: water, steel, aluminum, gold, gasoline, mercury, and more. A floatation indicator tells you whether the material sinks or floats in water, and a visual bar shows the specific gravity relative to osmium (densest stable element).
The reference table lists 20 materials from air to osmium with densities in three systems so you can locate nearby materials. Rows close to your current value are highlighted for quick comparison. This supports faster material screening and sanity checks in lab, manufacturing, and field estimation workflows. It is especially helpful when source data mixes imperial values from vendor sheets with SI values required in engineering calculations and compliance reports for design approval packages.
Engineers, chemists, and hobbyists specify density in different systems (SI vs. Imperial vs. specific gravity). This calculator bridges all of them and includes a material lookup table for quick reference, reducing conversion mistakes during reporting and design work across international teams, suppliers, and compliance workflows in fast-paced project environments and production schedules.
All conversions go through kg/m³: value_kgm3 = value × factor[fromUnit]. result = value_kgm3 / factor[toUnit]. Specific Gravity = density / 1000 (water at 4 °C).
Result: 7800 kg/m³ = 7.8 g/cm³ = 487.1 lb/ft³, SG = 7.8
Steel has SG of 7.8 — about 7.8 times denser than water.
Structural engineers select materials by density and strength. Aluminum (2,700 kg/m³) has about one-third the density of steel (7,800 kg/m³), which is why aircraft frames use aluminum alloys. Titanium (4,540 kg/m³) offers a middle ground with superior strength-to-weight ratio.
Archimedes' principle: a floating object displaces a weight of fluid equal to its own weight. A ship made of steel (SG 7.8) floats because its hull encloses a large volume of air, giving the overall ship an average density less than water.
Density of liquids varies with temperature. Water reaches maximum density at 3.98 °C (999.97 kg/m³). Heating water from 4 °C to 100 °C reduces its density to about 958 kg/m³ — a 4% decrease that drives convection currents.
Density is mass per unit volume (ρ = m/V). SI unit is kg/m³. Denser objects pack more mass into the same volume.
Specific gravity (SG) is the ratio of a substance's density to water at 4 °C (1000 kg/m³). SG < 1 means it floats; SG > 1 means it sinks.
Multiply by 1000. 1 g/cm³ = 1000 kg/m³.
Density has units (kg/m³). Specific gravity is a dimensionless ratio relative to water. Numerically SG equals density in g/cm³.
Ice has density ~917 kg/m³ (SG 0.917), less than liquid water at 1000 kg/m³. Water expands when it freezes — a unique property among common substances.
Multiply by 16.01846. Example: 100 lb/ft³ × 16.018 = 1,601.8 kg/m³.