Find the volume of a gas from its mass at any pressure and temperature. Covers CNG, air, nitrogen, oxygen, CO₂, hydrogen and more.
Conditions
−50 °C0 °C100 °C
Z
Gas volume at these conditions
—
Live gas chamber
At 0 °C, 1 atm
Gas density
Moles
Compression vs 1 atm
At 1 atm
Your gas
Bars use a log scale so very high compression stays visible.
How KG to Liters Gas Calculator Works?
KG to Liters Gas Calculator works by turning the mass of gas into moles (n = m ÷ M) and applying the ideal gas law V = Z · n · R · T ÷ P. The calculator holds 10 gases, including CNG (methane), air, nitrogen (N₂), oxygen (O₂), carbon dioxide (CO₂), hydrogen (H₂), helium, argon, propane vapour and butane vapour.
Mass1 kg methane
→
÷ M = 16.043 g/mol62.33 mol
→
Volume at STP1,397.1 L
1 kg of methane = 62.33 mol × 22.414 L/mol = 1,397.1 L at 0 °C (32 °F) and 1 atm.
5 steps to use KG to Liters Gas Calculator
Select the gas, including CNG, air, nitrogen or CO₂.
Enter the mass of gas in kilograms (kg), grams (g) or pounds (lb).
Set the absolute pressure in bar, atm or psi, and the gas temperature.
Enter the compressibility factor (Z), or keep 1 near atmospheric pressure.
Read the gas volume in liters (L) and cubic meters (m³).
KG to Liters Gas Calculator Formula
The KG to Liters Gas Calculator formula is V = Z · n · R · T ÷ P, with n = m ÷ M. The formula has 6 variables:
V (volume) is the gas volume in cubic meters (m³), shown in liters (L).
Z (compressibility factor) corrects for real-gas behaviour.
n (amount) is the moles of gas, from mass m ÷ molar mass M.
R (gas constant) is 8.314 J/(mol·K).
T (temperature) is the absolute temperature in kelvin (K).
P (pressure) is the absolute pressure in pascals (Pa).
V = Z · n · R · T ÷ Pn = m ÷ M
3 worked examples of the KG to Liters Gas Calculator formula
1 kg of air at 0 °C and 1 atm: 773.8 L.
1 kg of nitrogen at 20 °C and 1 atm: 858.7 L.
1 kg of methane at 200 bar and 15 °C (Z = 0.8): 5.97 L.
1 mole of an ideal gas fills 22.414 L at standard temperature and pressure (STP, 0 °C and 1 atm) and 24.04 L at normal temperature and pressure (NTP, 20 °C and 1 atm).
KG to Liters Gas Calculator Conversion Table
The KG to Liters Gas Calculator conversion table lists the liters in 1 kg of 9 gases at STP (0 °C, 1 atm) and NTP (20 °C, 1 atm).
Gas
M (g/mol)
STP (L)
NTP (L)
m³ at NTP
CNG / Methane
16.043
1,397.1
1,499.4
1.499
Air
28.965
773.8
830.5
0.830
Nitrogen (N₂)
28.014
800.1
858.7
0.859
Oxygen (O₂)
31.998
700.5
751.8
0.752
Carbon dioxide (CO₂)
44.010
509.3
546.6
0.547
Hydrogen (H₂)
2.016
11,118
11,932.1
11.932
Helium (He)
4.003
5,599.9
6,009.9
6.010
Argon (Ar)
39.948
561.1
602.2
0.602
Propane vapour
44.097
508.3
545.5
0.546
Propane vapour508 L
Carbon dioxide (CO₂)509 L
Argon (Ar)561 L
Oxygen (O₂)700 L
Air774 L
Nitrogen (N₂)800 L
CNG / Methane1,397 L
Liters in 1 kg of 7 gases at STP. Hydrogen (11,118 L) and helium (5,600 L) are left off the scale.
What Is KG to Liters Gas Calculator?
KG to Liters Gas Calculator is a tool that finds the volume of a gas from the mass of the gas at a set pressure and temperature.
A gas has no fixed density: the volume of 1 kg of gas shrinks as pressure rises and grows as temperature rises. The ideal gas law links mass, moles, pressure, temperature and volume.
1 kg of air fills 773 L at 0 °C and 1 atm.
1 kg of CNG (methane) fills 1,397 L at 0 °C and 1 atm.
Doubling the absolute pressure halves the gas volume at a fixed temperature.
What Are the Uses of KG to Liters Gas Calculator?
There are 4 main uses of KG to Liters Gas Calculator: CNG cylinder sizing, industrial gas supply, welding and lab gases and carbon dioxide accounting.
CNG cylinder sizing: A CNG car cylinder of 60 L holds 10.0 kg of methane at 200 bar and 15 °C (Z = 0.8).
Industrial gas supply: Gas suppliers bill nitrogen and oxygen by kilogram or cubic meter.
Welding and lab gases: Argon cylinders list gas volume in liters at 1 atm.
Carbon dioxide accounting: 1 kg of CO₂ fills 509 L at 0 °C and 1 atm.
Frequently Asked Questions
How many liters is 1 kg of CNG?
About 1,400 L of gas at 0 °C and 1 atm, or roughly 6 L when compressed to 200 bar at 15 °C (Z ≈ 0.8).
How many liters is 1 kg of air?
About 773 L at 0 °C and 1 atm, or 830 L at 20 °C.
What Z factor should I use?
Use 1 near atmospheric pressure. Methane at 200 bar and 15 °C is about 0.8; check gas tables for precise work.