Density Converters 10
Density is mass divided by volume — which makes it the one conversion on this site that asks you to think in three dimensions before you start. A cubic meter of water weighs 1,000 kg. A cubic foot of water weighs 62.4 lb. The same water, two volumes, two masses, one ratio: 1 g/cm³ = 1,000 kg/m³ = 62.427961 lb/ft³. Every converter here uses exact constants derived from the SI definitions and the 1959 yard/pound agreement — no approximations, because density is where materials science meets money.
Why Density Conversion Bites People
Density is the unit conversion where the numbers look friendly and the physics bites. A materials datasheet says "2.7 g/cm³" — that's aluminum, instantly recognizable. The structural engineer converts it to 2,700 kg/m³ for the FEA model; the US fabricator wants 168.6 lb/ft³ for the weight estimate; the aerospace buyer checks 0.0975 lb/in³ against the aircraft spec. All four numbers describe the same aluminum, and the conversions between them are exact. The trap is the cube: because density multiplies a length by itself twice, any error in the length conversion gets cubed. A 1% error in a unit factor is a 3% error in density — which is why the constants on this page carry full precision.
Density also anchors the "mass → volume → density" triangle this site now covers end to end. The weight & mass page handles the numerator; the volume page handles the denominator; this page combines them. If you know any two of the three — mass, volume, density — you can find the third, and the converters on this page give you the density half of that chain.
What's on this page
Ten converters covering the five density unit families that actually show up in engineering work — kilograms per cubic meter (SI), grams per cubic centimeter (materials science shorthand), pounds per cubic foot (US construction), pounds per cubic inch (aerospace and metals), and grams per liter (water chemistry and solutions). Every factor is exact. The anchors to remember: 1 g/cm³ = 1,000 kg/m³ (a factor of 1,000 — the cube of 10), 1 lb/ft³ = 16.018463 kg/m³ (the 1959 pound over the 1959 foot, cubed), and 1 g/cm³ = 62.427961 lb/ft³. Everything else on this page derives from those three. For the mass side of the ratio, see the weight & mass converters; for the volume side, the volume page; for density in a moving fluid, the speed and frequency families handle the flow side.