Kilograms per Liter to Grams per cm³ Density Converter
Common Conversions
| kg/L | g/cm³ |
|---|---|
| 0.1 | 0.1 |
| 0.5 | 0.5 |
| 1 | 1 |
| 2 | 2 |
| 5 | 5 |
| 10 | 10 |
| 25 | 25 |
| 50 | 50 |
| 100 | 100 |
| 1000 | 1000 |
Why this conversion matters in chemistry
Bulk-chemical density specs come in kg/L on the supplier data sheet — industrial-grade glycerol at 1.261 kg/L, ethylene glycol at 1.1132 kg/L. The bench QC technician confirms identity against a g/cm³ entry on the certificate of analysis using a digital densimeter. The numbers are the same, since 1 L holds 1000 cm³ and 1 kg is 1000 g; the prefix factors cancel. The identity is the ordinary type cast at the boundary between bulk-tank density specifications and the lab-scale identity check before releasing a tanker shipment to production.
Formula
Where the factor comes from
The prefixes cancel, but they only cancel cleanly because of a decision taken in 1964. The liter is now defined as exactly one cubic decimeter, and a cubic decimeter holds exactly 1000 cm³; the kilogram holds exactly 1000 g. Carrying both through, 1 kg/L = 1000 g / 1000 cm³ = 1 g/cm³, an identity with no measured quantity anywhere in it. From 1901 until that redefinition the liter was instead the volume occupied by one kilogram of water at its density maximum, which turned out to be about 28 parts per million larger than a cubic decimeter. Under the old definition kg/L and g/cm³ genuinely differed, in the fifth decimal place. Densities quoted to six figures in mid-century literature are the one place that ghost still surfaces.
Precision and significant figures
Because the conversion is an identity, every digit transfers unchanged and there is nothing to round — which puts the whole question of precision back on the density measurement and the temperature it was made at. An oscillating U-tube densimeter will resolve five or six decimals, but that resolution only means anything with the cell thermostatted, since water near room temperature loses roughly 0.0002 g/cm³ for every degree it warms. The fourth decimal is therefore a temperature statement as much as a density one. A supplier figure of 1.261 kg/L with no temperature attached supports three decimals at most, and copying it into g/cm³ does not earn it a fourth.
Worked Examples
Water at 4 °C — the density anchor that pins both notations together.
Seawater — the typical density figure for any oceanographic-sample calculation.
Acetone at 20 °C — useful as a low-density organic-solvent reference.
Common mistakes
Assuming all density prefixes cancel this way
The free pass covers exactly two families: kg/L, g/cm³ and g/mL are numerically identical, and so are kg/m³ and g/L. Crossing between the families costs a factor of 1000 in either direction. Glycerol is 1.26 g/cm³ and 1260 g/L, and both look like reasonable density values on a data sheet, so the error does not announce itself.
Specific gravity copied straight into g/cm³
Supplier sheets often list relative density or specific gravity — a dimensionless ratio against water at a stated temperature. Multiplying by water's density at that reference gives g/cm³. Read a 20/20 °C value as g/cm³ directly and you overstate it by about 0.18 percent. A 60/60 °F value needs a different reference and describes the liquid at 15.6 °C, not 20 °C — two corrections, both in the third decimal.
Bulk density read as material density
Powders and granular solids are frequently specified in kg/L, but that figure is a poured or tapped bulk density that includes the void space between particles. A crystalline solid typically pours at roughly half its crystallographic density. Converting that number to g/cm³ and using it to work out the volume a mass of crystal occupies will overstate the volume substantially.