What is the relationship between specific volume and density?

Specific volume is the reciprocal (inverse) of density. If density is ρ (kg/m³), specific volume v = 1/ρ (m³/kg). They convey the same information in different forms. Density focuses on mass per space; specific volume focuses on space per mass.

Why is specific volume used in thermodynamics?

Specific volume appears directly in thermodynamic equations like the ideal gas law (Pv = RT, where v is specific volume). It's used in steam tables because it varies dramatically with temperature and pressure. Work in expansion/compression processes is calculated using specific volume.

How does specific volume change with temperature?

Specific volume generally increases with temperature as substances expand. Gases show large changes—specific volume roughly doubles from 0°C to 273°C at constant pressure. Liquids expand less. Water is unusual: specific volume decreases slightly from 0°C to 4°C before increasing.

What is the specific volume of steam?

At 100°C and 1 atm, steam has a specific volume of about 1.67 m³/kg—roughly 1670 times that of liquid water (0.001 m³/kg). This dramatic expansion is why steam engines work and why steam burns are severe. Specific volume decreases as pressure increases.

How do I convert density to specific volume?

Simply calculate 1 divided by density. If density is in kg/m³, you get m³/kg. If density is in g/cm³, you get cm³/g. Example: Aluminum density = 2.7 g/cm³, so specific volume = 1/2.7 = 0.37 cm³/g = 0.00037 m³/kg.

Volume spécifique Converter

About Specific Volume Conversion

Specific volume is the inverse of density—it measures volume per unit mass rather than mass per unit volume. While density tells you how much mass fits in a given space, specific volume tells you how much space a given mass occupies. This property is particularly useful in thermodynamics, HVAC engineering, steam power systems, and gas calculations where tracking how substances expand or compress is essential.

The SI unit is cubic meters per kilogram (m³/kg). Specific volume increases with temperature as substances expand—this is dramatically visible when water boils into steam, expanding roughly 1,600 times in volume at atmospheric pressure. Understanding specific volume is crucial for sizing pipes, designing pressure vessels, interpreting steam tables, calculating compressor performance, and analyzing refrigeration cycles where fluids change phase repeatedly.

Our converter handles all standard specific volume units for thermodynamic and engineering applications, from power plant design to HVAC system analysis.

Common Specific Volume Conversions

From	To	Multiply By
m³/kg	L/kg	1000
L/kg	m³/kg	0.001
m³/kg	ft³/lb	16.018
ft³/lb	m³/kg	0.06243
m³/kg	cm³/g	1000
cm³/g	m³/kg	0.001
L/g	m³/kg	1
ft³/lb	L/kg	62.43
gal/lb	m³/kg	0.008345
m³/kg	gal/lb	119.83

Specific Volume Unit Reference

Cubic meter per kilogram (m³/kg) – The SI unit of specific volume. Water at 4°C has specific volume of 0.001 m³/kg (or 1 L/kg). Gases have much higher values—air at sea level is about 0.82 m³/kg, and steam at 100°C and 1 atm reaches 1.67 m³/kg. This unit appears directly in the ideal gas law written as Pv = RT, where v is specific volume.

Liter per kilogram (L/kg) – Convenient for liquids and easily visualized. 1 L/kg = 0.001 m³/kg exactly. Water ≈ 1 L/kg at room temperature, making comparisons intuitive. Gasoline has specific volume around 1.33 L/kg (it's less dense than water). Common in chemical process industries.

Cubic foot per pound (ft³/lb) – US customary unit widely used in HVAC, steam engineering, power plants, and industrial applications. Water ≈ 0.016 ft³/lb. Steam tables in US engineering handbooks report specific volume in ft³/lb. Essential for sizing ducts, pipes, and heat exchangers in American engineering practice.

Cubic centimeter per gram (cm³/g) – Equal to mL/g, common in chemistry and laboratory work. Numerically identical to L/kg. Water = 1 cm³/g provides a convenient reference. Often used when working with small samples or precise laboratory measurements.

Gallon per pound (gal/lb) – Occasionally used in US for liquid applications, particularly in the petroleum and chemical industries. Water ≈ 0.12 gal/lb (US gallon). Useful when dealing with tank capacities and liquid handling where gallons are the standard volume measure.