Weight per Gallon of Different Gases

By contrast with liquids, gases are compressible and can exist in various states depending on temperature and pressure. This means that their density, and therefore their weight per gallon, can vary significantly. There are several reasons that show why knowing different gases’ weight per gallon is so important.

First, it is significant for fuel efficiency calculations when operators take advantage of knowing how much energy is available per unit of weight. Second, it is useful for tank capacity planning, when sizing storage and transport tanks according to volume and weight. Third, there is a factor of regulatory compliance – meeting the requirements for weight limits when shipping hazardous materials. Finally, yet importantly, knowing the exact weight per gallon of a certain gas allows for accurate pricing and billing, especially in industries where gas is sold by volume or weight.

While cubic feet or cubic meters are common units for gases in natural form, gallon-based weight measurements are essential for liquefied gases and fuel applications in commercial and residential sectors.

Below is a breakdown of some of the most commonly used gases and their approximate weight per gallon in liquid or compressed form at standard conditions (unless otherwise specified).

LPG (Liquefied Petroleum Gas)

• Propane: Approx. 4.24 lbs (1.92 kg) per gallon 

• Butane: Approx. 4.81 lbs (2.17 kg) per gallon 

Propane and butane are popular for heating, cooking, and fuel applications. While both are LPGs, they differ slightly in density. Propane is widely used in colder climates due to its lower boiling point.

Methane (Natural Gas)

• CNG (Compressed Natural Gas): Approx. 0.31 lbs (0.14 kg) per gallon at 3600 psi (252 bar)

• LNG (Liquefied Natural Gas): Approx. 3.5 lbs (1.58 kg) per gallon

Natural gas is primarily methane and can be delivered in either compressed or liquefied form. LNG has a much higher energy density than CNG, making it more suitable for long-distance transport.

Ammonia (NH₃)

• Anhydrous Ammonia: Approx. 5.15 lbs (2.33 kg) per gallon

Ammonia is used in refrigeration and agriculture. It is heavier than many hydrocarbons and requires specialized handling due to its corrosive nature.

Carbon Dioxide (CO₂)

• Liquid CO₂: Approx. 8.47 lbs (3.83 kg) per gallon

Liquid CO₂ is used in beverage carbonation, fire suppression, and industrial processes. It is one of the heaviest gases when liquefied.

Hydrogen (H₂)

• Liquid Hydrogen: Approx. 0.59 lbs (0.26 kg) per gallon

Hydrogen has the lowest density of any element. Although it has high energy per mass, its energy per volume is low, which is a challenge for storage and transport.

Certain variables can influence the actual weight of a gas per gallon. First, it is states of the gas – compressed, liquefied, or cryogenic. Liquid states are typically denser and heavier per gallon. Second, it is temperature and pressure. Both significantly affect gas density. For instance, CNG at higher pressure has more mass in the same volume. 

The third variable is a composition. Gases like LPG can have varying ratios of propane and butane, which affects total weight. The last factor is purity levels. Industrial gases may include trace impurities, slightly altering their density.

To help visualize the differences between various gases, here is a comparative table.

These values are approximate and can vary depending on pressure, temperature, and purity. For accurate applications, always refer to technical data sheets or consult your gas supplier.

Understanding how much a gas weighs per gallon is vital across industries such as fuel supply, logistics, and energy planning. For example, fuel delivery enterprises use this data to size tanks and optimize delivery routes. Compressed natural gas companies calculate vehicle range and tank filling capacities. CNG providers need to ensure regulatory compliance with transport weight limits. LPG distributors rely on these figures to determine customer billing and storage solutions.

If you are involved in the storage or transportation of industrial or fuel gases, there are some essential factors to keep in mind. When handling, storing, or transporting gases in any form, consider the following:

• Verify density under actual working conditions, not just standard lab conditions.

• Use certified storage tanks and safety equipment, especially for pressurized gases.

• Consult with experienced gas suppliers to select the right type and quantity of fuel or industrial gas.

The process of gas storage and delivery will always be smooth, provided you consider all the aforementioned aspects.

Whether you are dealing with propane tanks, LNG terminals, or compressed hydrogen fuel, knowing the weight per gallon of different gases is fundamental for safe, efficient, and cost-effective operations. From heating systems to transportation fleets, these values help you make informed decisions about gas type, storage, and supply chain logistics.

At I-Maximum, we support businesses and industries by offering insights into gas sourcing, energy alternatives, and market dynamics. Whether you are working with a CNG supplier or managing a large-scale LPG installation, precision and understanding of gas metrics are vital. Always rely on verified data and trusted industry partners when planning your gas infrastructure.