How the Gas Mass-to-Volume Converter Works
The Gas Mass-to-Volume Converter divides gas mass by gas density at the chosen temperature and pressure. The default 0.0012 kg/L (1.2 kg/m³) fits air near room conditions.
Pick the gas
Look up the molar mass of the gas in the table.
Work out the density
Use ρ = P × M ÷ (R × T), or read the 0°C and 20°C values from the table.
Enter mass and density
Type the kilograms and the density in kg/L into the number box.
Read the liters
Divide by 1,000 for cubic meters of gas.
Gas Mass-to-Volume Converter Formula
The gas volume formula is the ideal gas law: V = (m ÷ M) × (R × T ÷ P). One mole of ideal gas fills 22.414 L at 0°C and 1 atm.
- M
- Molar mass, kg/mol
- R
- Gas constant, 8.314 J/(mol·K)
- T
- Absolute temperature, K (°C + 273.15)
- P
- Absolute pressure, Pa (1 atm = 101,325 Pa)
Worked Examples
- 1 kg of helium at 20°C, 1 atm: (1,000 ÷ 4.003) × 24.055 L = 6,009 L.
- 1 kg of argon at 0°C: (1,000 ÷ 39.95) × 22.414 L = 561 L.
- 1 kg of methane at 20°C: (1,000 ÷ 16.04) × 24.055 L = 1,500 L.
Gas Mass-to-Volume Converter Conversion Table
1 kg of hydrogen fills about 11.9 m³ at 20°C and 1 atm, while 1 kg of CO₂ fills 0.547 m³. The table lists 10 gases.
| Gas | Molar Mass (g/mol) | Density at 0°C (kg/m³) | Density at 20°C (kg/m³) | Liters per kg at 0°C | Liters per kg at 20°C |
|---|---|---|---|---|---|
| Hydrogen (H₂) | 2.016 | 0.0899 | 0.0838 | 11,118 | 11,932 |
| Helium (He) | 4.003 | 0.1786 | 0.1664 | 5,599 | 6,009 |
| Methane (CH₄) | 16.040 | 0.7156 | 0.6668 | 1,397 | 1,500 |
| Ammonia (NH₃) | 17.030 | 0.7598 | 0.7080 | 1,316 | 1,413 |
| Nitrogen (N₂) | 28.013 | 1.2498 | 1.1645 | 800 | 859 |
| Air (dry) | 28.965 | 1.2923 | 1.2041 | 774 | 830 |
| Oxygen (O₂) | 31.999 | 1.4276 | 1.3302 | 700 | 752 |
| Argon (Ar) | 39.948 | 1.7823 | 1.6607 | 561 | 602 |
| Carbon dioxide (CO₂) | 44.010 | 1.9635 | 1.8296 | 509 | 547 |
| Propane (C₃H₈) | 44.097 | 1.9674 | 1.8332 | 508 | 546 |
Ideal gas values at 1 atm (101.325 kPa). Real CO₂, ammonia and propane deviate by 0.5–1.5% at these conditions.
What is a Gas Mass-to-Volume Converter?
A Gas Mass-to-Volume Converter is a calculator that converts a gas mass into volume at a set temperature and pressure using gas density from the ideal gas law.
Gases have no fixed volume. The same 1 kg of nitrogen fills 800 L at 0°C and 1 atm, 859 L at 20°C, and just 4 L inside a 200 bar cylinder.
Industry quotes gas volumes at a reference state. Normal cubic meters (Nm³) use 0°C and 1 atm; standard cubic meters (Sm³) often use 15°C and 1 atm; US standard cubic feet (scf) use 60°F and 14.696 psi.
What are the Uses of a Gas Mass-to-Volume Converter?
There are 4 main uses of a Gas Mass-to-Volume Converter.
Cylinder contents
Gas suppliers convert filled kg into Nm³ on labels.
Balloon and lift
Event teams size helium orders for balloons.
Emissions reporting
Analysts convert tonnes of CO₂ or methane into volume.
Process design
Engineers convert mass flow into volume flow for pipes and fans.