Specific Volume & Fluid Density Converter

Thermodynamics, Fluid Mechanics & Specific Volume Metrology

Specific volume (v) is the volume occupied by a unit mass of a substance, equal to the reciprocal of density:

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• Unit Conversion Relationships (ISO 80000-4 Standards)**:

• 1 m^3/kg: SI base unit of specific volume

• 1 ft^3/lb: 0.062428 m^3/kg 1 m^3/kg = 16.0185 ft^3/lb

• 1 L/kg: 0.001 m^3/kg = 1 cm^3/g = 1 mL/g

• 1 gal (US)/lb: 0.0083454 m^3/kg

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• Reciprocal Density Relationship**:

ρ = (1) / (v)

ρ_lb/ft^3 = (1) / (v)

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• Standard Thermodynamic State Benchmarks**:

• Liquid Water (20°C): v = 0.001002 m^3/kg 0.01605 ft^3/lb ρ = 998.2 kg/m^3

• Gasoline Fuel: v = 0.001333 m^3/kg 0.02135 ft^3/lb ρ = 750.0 kg/m^3

• Dry Air (STP): v = 0.8350 m^3/kg 13.38 ft^3/lb ρ = 1.198 kg/m^3

• Saturated Steam (100°C): v = 1.673 m^3/kg 26.80 ft^3/lb ρ = 0.598 kg/m^3

How to Use This Calculator

Enter your Specific Volume Magnitude (v) (e.g. 0.001 in v), From Specific Volume Unit — choose from Cubic Meters per Kilogram (m³/kg - SI Base Unit), Liters per Kilogram (L/kg), Cubic Feet per Pound (ft³/lb - Imperial / US), To Specific Volume Unit — choose from Cubic Meters per Kilogram (m³/kg), Liters per Kilogram (L/kg), Cubic Feet per Pound (ft³/lb), and Thermodynamic Fluid Benchmark — choose from Custom Specific Volume, Liquid Water at 20°C (0.0010018 m³/kg) → 1.002 L/kg | 0.01605 ft³/lb | ρ = 998.2 kg/m³, Saturated Steam at 100°C / 1 atm (1.673 m³/kg) → 1,673 L/kg | 26.80 ft³/lb | ρ = 0.598 kg/m³. Results update instantly as you type — adjust any value to compare scenarios.

The Formula

Reciprocal Fluid Density: rho = 1 / v (kg/m^3 and lb/ft^3)

Worked Example

A mechanical engineer modeling a boiler finds that water boiling into saturated steam at 100°C expands from v = 0.00104 m^3/kg to v = 1.673 m^3/kg, decreasing its density from 958 kg/m^3 to just 0.60 kg/m^

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Understanding Your Result

Geometric calculations assume ideal shapes — real-world measurements should include a 5–15% tolerance for irregular shapes, cutting waste, and installation overlap. For construction applications: always verify calculated areas match your physical measurements before ordering materials. Standard practice is to measure the same dimension twice from different reference points and use the average. Express results in the units required by your supplier or building permit — conversions between cubic yards, cubic feet, and cubic meters must be precise for material orders.