Click here for metric conversions and Australian gas cylinder sizes

The easiest way to answer most of them is with a Propane conversion chart or table…

 

Propane Conversion Chart

Units of Measure	Equivalent Units
1 US Gallon	4.23 Pounds (4 Pounds 3.7 Ounces)
1 Pound	0.236 Gallons (30.2 Ounces)
1 US Gallon	91,502 BTU @ 60ºF
1 US Gallon	0.915 therm
1 cubic foot	2,488 BTU @ 60ºF
1 US Gallon	36.4 ft3 Gas
1 Litre	23,700 BTU

  Note: Some numbers have been rounded.

Propane BTU Conversion - Propane BTU per Gallon

Propane BTU conversion is the most common conversion measures of propane energy content including propane BTU per gallon, propane BTU per cubic foot, propane therms to gallons and propane gallons to pounds conversion.

BTU is the acronym for British Thermal Unit, a unit of energy.

Propane BTU conversion is needed as gas appliances are rated in Propane BTU, based on the required energy input.

Propane BTU conversion is also used by gas companies to determine total gas load on a system when everything is running on maximum.

One BTU is the amount of heat required to raise the temperature of 1lb of water by 1°F, at sea level.

The relative efficiency of the propane BTU conversion input into the gas appliance determines the heat output.

More propane BTU conversion energy content facts:

Propane BTU per Gallon - How Many BTUs are in a Gallon of Propane - 91,502 BTU

In the propane BTU per gallon conversion, there are 91,502 BTU in 1 gallon of propane gas. "How many BTUs are in a gallon of propane?" is a very common question. It helps to calculate the gas consumption of an appliance, based on the BTU rating of the appliance.

In the propane BTU per gallon conversion, to convert BTU to gallons of propane just divide BTU by 91,502.

Propane BTU per Gallon: is 91,502 BTU (Propane BTU per galllon).

Propane BTU per 100 gallon propane gas tank is 9,150,200 BTU.

Propane BTU per Gallon of a 20lb tank: 4.73 gallon (20lb) propane tank is 432,804 BTU.

So, if you divide 91,502 by the BTU rating of the appliance, you can calculate how much propane will be used by the appliance per hour.

You can also calculate how many hours a certain propane gas bottle size will last by dividing the BTU of the contents by the BTU rating of the appliance.

The following are the values for BTU in 1 gallon of propane gas and per ft³ of propane gas, as well as the values in MJ, litres and watts:

• Propane BTU per Gallon: 1 Gallon = 91,502 BTU @ 60ºF

• Propane BTU per Cubic Foot (ft³): 1 cubic foot = 2,488 BTU @ 60ºF

• Propane Therms to Gallons: 0.915 therms = 1 Gallon

• Propane Gallons to Pounds Conversion: 1 Gallon = 4.23 Pound

• Propane BTU per MJ: 1MJ = 948 BTU

• Propane BTU per Watt: 1 watt = 3.41214 BTU/hr

• BTU per Litre of Propane Liquid: 1 Litre = 23,700 BTU

Convert BTU to Gallons of Propane

If you need to convert BTU to gallons of propane, you simply divide the entire BTU requirement by 91,502 BTU. So, if you know the BTU/hr consumption of an appliance and multiply by how many hours you intend to run it, you arrive at the total propane BTU requirement. Then you divide the total propane BTU requirement by 91,502 to determine how many gallons of propane will be required.

As an example, you have a gas heater with a 23,700 BTU (25MJ) per hour consumption and you want to run it for 8 hours.

23,700 x 8 = 189,600 BTU requirement

189,600 ÷ 91,502 = 2.072 gallons of propane required

Propane Therms to Gallons: Therms per Gallon & Gallons per Therm

For propane therms to gallons, there are 1.1 (propane) therms per gallon. This is for US gallons of propane.

• Propane Therms per Gallon: 1 Therm = 1.1 US gallons of propane

• Propane US Gallons per Therm: 1 (propane) therm per 0.915 gallon

• Propane BTU per Therm: 1 therm = 100,067 BTU

So, if you want to convert propane therms to gallons, it is 1 (propane) therm per 0.915 gallon.

Propane BTU per Liter = 23,700 BTU per Liter - Propane BTU Conversion for Volume

Propane BTU per liter = 23,700 BTU per liter.  In propane BTU per liter, which is a propane BTU conversion for volume, propane BTU per liter combines an old imperial energy measurement - BTU - with a metric volume measurement - liter.

Propane BTU per liter = 23,700 BTU per liter of propane. 1MJ equals 948BTU, so to get an equivalent number of BTU, just multiply the MJ rating by 948.

1L = 25 MJ. So, to calculate propane BTU per liter:  25 MJ x 948 = 23,700 BTU

Combining metric and imperial measures is not typical but it can be easily calculated, as shown.

CFH to BTU Propane - Propane BTU Conversion for Gaseous Volume

In the propane BTU conversion for gaseous propane, the CFH to BTU propane is based on the flow rate of CFH being Cubic Foot per Hour, so 1 CFH = 2,488 BTU per hour of propane.

Remember that Propane BTU per cubic foot (ft³): 1 cubic foot of propane = 2,488 BTU @ 60ºF

So, one CFH equals 2,488 BTU per hour: 1CFH = 2,488BTU/hr

Example of a CFH to BTU propane calculation:

If the flow rate is 20 cubic feet per hour, the total BTU of heat produced per hour would be 2,488 BTU/cubic foot x 20 cubic feet/hour = 49,760 BTU per hour.

Propane Bottle-Cylinder Sizes - Domestic LPG Cylinder Dimensions

Propane cylinder-bottle sizes incorporate domestic LPG cylinder dimensions including the 100lb propane cylinder size, 200lb propane bottle size and 420lb propane cylinder sizes.

The various propane bottle sizes exist because different people used different amounts of gas and the propane cylinder sizes are selected accordingly.

Domestic propane bottle-cylinder sizes are the same for LPG bottle sizes and propane bottle sizes, as they are the same gases.  Propane is also called LPG, as is butane. 

For Australian LPG gas bottles & cylinders:

See metric conversions of LPG in kg, Litres, MJ, kWh, BTU & m³

A 'full' 20 pound propane tank would contain 4.73 gallons of propane.

A 20lb (4.73 gallon) propane tank has 432,804 BTU, based on propane BTU per gallon of 91,502 BTU @ 60ºF.

Note that in some US tank exchange programs, the fill is something less than 20 pounds and is labelled accordingly.

The image above is a typical 20 pound (9kg) propane tank.

23.64 gallons are in a 100 lb propane tank, based on the conversion chart above.

A 100lb (22.9 gallon) propane tank has 2,095,396 BTU, based on propane BTU per gallon of 91,502 BTU @ 60ºF.

A 100 pound tank is roughly the same size as a 45kg gas bottle.

They are small enough to be exchanged or tanker filled.

The image to the right is of a typical 100 pound propane tank.

Unlike water, 1 pint of propane does not weigh ≈ 1lb.  It actually weighs 0.51lbs.

This is because the density or specific gravity of propane is only about half that of water. 

Converting from weight to volume, 1lb of propane @ 60ºF has a volume of 0.24 US gallons.

Conversely, 1 US gallon of propane @ 60ºF only weighs 4.23lbs, instead of the 8.34lbs it would weigh if it was water.

Important Note:

All volumes are quoted in US gallons, as opposed to imperial gallons.

Imperial gallons are 20% larger.

Propane expands about 270 times in volume when it goes from liquid to gas. 

So, 1 US gallon of liquid propane equals 36.4 ft³ of gaseous propane

Tare weight is the empty weight of the gas bottle-cylinder.  

Along with the gas bottle dimensions, they can vary greatly by manufacturer and date of manufacture. 

For example, older bottles tend to be heavier than more recent versions.

 

 

 

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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.