LPG (propane) Gas Unit Conversions: Gas in kg, Litres, MJ, kWh & m³
Also Propane Gas Unit Conversion in Pounds, Gallons, BTU, Therms & ft³
We are frequently asked about the various LPG - propane - gas unit conversion (LP gas unit conversion) values. The first table shown below covers most of the common units of measure and gas bottle-cylinder sizes for Australia, including kg, litres, MJ, kWh & m³ (e.g. LPG gas unit conversion of kg to litres is 1kg = 1.96L).
Litre (Liter) to kg & kg to Litres
The two most common conversions are litre (liter) to kg and kg to litre. It is important to note that water and LPG (propane) have different conversion formulas because they have different density.
Water Litre to kg: 1Litre = 0.999975 kg, so for all practical purposes 1L = 1kg
LPG (propane) Litre to kg: 1 Litre = 0.51kg
Water kg to Litre: 1kg = 1 litre
LPG (propane) kg to Liter: 1kg = 1.96 litres
LPG – Propane – Gas Unit Conversion Formulas (Metric):
LPG (propane) kg to litres: 1kg = 1.96L
LPG (propane) litres to kg: 1L = 0.51kg
*LPG (propane) kg to m³: 1kg = 0.53m³
^LPG (propane) m³ to kg: 1m³ = 1.89kg
*LPG (propane) litres to m³: 1L = 0.27m³
^LPG (propane) m³ to litres: 1m³ = 3.70L
LPG (propane) MJ to kWh: 1MJ = 0.278kWh
LPG (propane) kWh to MJ: 1kWh = 3.6 MJ
LPG (propane) litres to MJ: 1L = 25MJ
LPG (propane) MJ to litres: 1MJ = 0.042L
LPG (propane) kg to MJ: 1kg = 49MJ
LPG (propane) MJ to kg: 1MJ = 0.02kg
LPG (propane) litres to kWh: 1L = 6.9kWh
LPG (propane) kWh to litres: 1kWh = 0.145L
LPG (propane) kg to kWh: 1kg = 13.6kWh
LPG (propane) kWh to kg: 1kWh = 0.074kg
LPG (propane) L to BTU: 1L = 23,700 BTU
LPG (propane) kg to BTU: 1kg = 46,452 BTU
LPG Specific Gravity - Density
LPG Gas Consumption in Megajoules
Appliance Output in kWh
BTU to MJ Conversion
LPG energy content is expressed in BTU and MJ - Megajoules.
BTU, or British Thermal Unit, is another older measure of heat output based on the Imperial System.
As previously mentioned, BTU is used in the USA instead of MJ.
One BTU is the energy required to raise the temperature of 1 pound of liquid water by 1°F, at sea level.
1MJ equals 948BTU, so to get an equivalent number of Megajoules, just divide the BTU rating by 948.
LPG (propane) BTU per Liter - LPG Energy Content
LPG energy content is expressed in BTU per litre. LPG - Propane BTU per liter = 23,700 BTU per litre
This is based on 1MJ equalling 948BTU, so to get an equivalent number of BTU, just multiply the MJ rating by 948
So, as 1L = 25 MJ then 25 MJ x 948 = 23,700 BTU per litre
LPG (propane) BTU per KG - LPG Energy Content
LPG energy content is also expressed in BTU per kg. LPG - Propane BTU per kg = 46,452 BTU per kg
Since 1kg of LPG = 1.96L, then based on the above 1.96 x 23,700 BTU/L = 46,452 BTU. So, 1kg = 46,452 BTU per kg
Combining metric and imperial measures is not typical but it can be easily calculated.
LPG Liquid to Gas Volume Expansion
LPG cubic meter to kg and LPG kg to cubic meter (m³)
When comparing LPG cubic meter to kg (m3 to kg) you are comparing LPG volume in its gaseous state (cubic meter) to the mass of LPG liquid (kg). To convert LPG cubic meter to kg you simply use the LPG conversion formula: LPG cubic meter (m3) = 1.8315 kg.
The more detailed explanation for LPG cubic meter to kg is one LPG cubic meter (m3) of gas equals to 1.8315 kg of liquid LPG (propane) at 25 °C (77 °F). LPG cubic meter to kg (m3 to kg) varies with temperature.
The same is true of kg to m³ conversion.
LPG kg to cubic meter: 1kg = 0.546 m3 (propane)
For butane LPG cubic meter to kg: 1kg = 0.4084 m3 at 25 °C (77 °F)
For butane LPG kg to cubic meter: 1m3 = 2.4486kg
Gas Bottle Tare Weight
Measuring LPG by Pressure
When LPG (propane) is stored in a gas bottle, it is under pressure.
The term “pressure” refers to the average force per unit of area that the gas exerts on the inside walls of the gas bottle.
The pressure is measured in kilopascals (kPa).
“Bar” is yet another unit of measure for pressure. 1 Bar = 100 kPa, so it is metric based but not an SI unit of measure.
LPG pressure can vary greatly based on temperature.
The level of fill in the gas bottle comes into play when the LPG is being used, as it affects the rate of vapourisation.
As LPG is a liquefied gas, the pressure inside the cylinder will remain the same from full to empty (after the last of the liquid LPG is used), then the pressure will fall quickly as the last of the LPG vapour is used.
The use of Pressure as a measurement in LPG use is very limited.
A steady Pressure only shows that liquid LPG is inside the cylinder, and not how much liquid is left.
In the US, pressure is measured in pounds per square inch (psi).
Psi is defined as 1 pound of force applied per square inch. As a comparison, 1 psi = 6.89476 kPa.
LPG (Propane) Gas Unit Conversion Table: kg, Litres, MJ, kWh & m³
LPG Cylinder Capacity in Litres
LPG cylinder capacity in litres goes from a small LPG cylinder capacity of 7.25 litres for a 3.7kg LPG cylinder to a large LPG cylinder capacity of 411 litres for a 210kg LPG cylinder. The chart below shows LPG cylinder capacity in litres for the 7 most popular sizes of LPG cylinder based on 1.96 litres of LPG cylinder capacity per kilogram (1kg = 1.96L).
LPG cylinder capacity in litres is considered full at 80%, to allow for ullage. Ullage is the empty LPG cylinder capacity at the top of the cylinder that provides room for expansion of the gas vapour.
See accompanying illustration of LPG cylinder capacity in litres full at 80%.
LPG Cylinder Capacity in Litres Comparison Chart
LPG Cylinder Size in kg
|LPG Cylinder Capacity in Litres|
This chart of LPG cylinder capacity in litres is based on propane at 1kg = 1.96L
The capacity of an LPG cylinder in litres can change if sold by the kg, as propane has 1.96L per kg whilst butane has only 1.724L per kg. This is because the two gases have different specific gravity.
Propane Gas Unit Conversions Table: Pounds, Gallons, BTU, Therms & ft³
For our friends in the USA:
Propane gas unit conversion values in US gallons, pounds, BTUs, therms and cubic feet. The table below shown covers most of the common units of measure and gas bottle-cylinder sizes for the USA.
Propane Gas Unit Conversion Formulas (US Units of Measure):
Propane Gallons to Pounds: 1Gal = 4.23lbs
Propane Pounds to Gallons: 1lb = 0.24 Gallons
Propane Gallons to BTU: 1 Gal = 91,502 BTU
Propane Pounds to BTU: 1lb = 21,594 BTU
*Propane Gallons to ft3: 1 Gal = 36.38ft3
*Propane Pounds to ft3: 1lb = 8.59 ft3
BTU to Therms: 1 BTU = 0.000009993 Therms
Therms to BTU: 1 Therm = 100,067 BTU
45 kg LPG Gas Bottles
45 kg gas cylinder sizes are the most common size for home use
This is the size used for our Home Gas Bottle Exchange Service
They are also used with our Automatic Tanker Delivery Service
A typical installation has two 45kg gas bottles
Capacity: 88 litres
90 kg LPG Gas Cylinders
90 kg gas cylinder sizes are the second most common size for home use
This size is commonly used with our Automatic Tanker Delivery Service
A typical installation has one cylinder
90 kg is also used with our Underground LPG Gas Storage System
Capacity: 176 litres
210 kg LPG Gas Cylinders
210 kg gas cylinder sizes are provided for high volume use
Larger storage vessels are also available, when needed
Filling is via our Automatic Tanker Delivery Service
Capacity: 411 litres
Comments, questions or feedback?
The information in this article is derived from various sources and is believed to be correct at the time of publication. However, the information may not be error free and may not be applicable in all circumstances.