120-Gallon Propane Tank Dimensions (Horizontal + Vertical V-120)

Even before getting a 120-gallon propane tank, it is useful to know the exact 120-gallon propane tank dimensions. Knowing the footprint, including length, width, and empty weight will help you plan out the installation of this aboveground torpedo propane tank. That’s why we will list all relevant 120-gallon propane dimensions.

Luckily, a 120-gallon propane tank has standardized dimensions. That means that the size of a 120-gallon propane tank is determined; all of these tanks have the same size. What you need to know is that we have two kinds of 120-gallon propane tanks (each has different dimensions):

  • Vertical 120-gallon propane tank. This is the upright cylinder type of propane tank.
  • Horizontal 120-gallon propane tank. This is a torpedo-type propane tank that you put on your lawn.
dimensions of 120 gallon horizontal vs vertical propane tanks
2 types of 120-gallon propane tanks: Horizontal (on the left) and vertical (on the right). The vertical tank is basically a cylinder that is sometimes referred to as a V-120 cylinder.

Both 120-gallon tanks can hold up to 96 gallons of propane when full (not 120 gallons). That’s due to the 80% rule; all propane tanks can be filled up to 80% of their maximum capacity. This is a safety measure; at higher temperatures, propane expands and produces increased pressure on the inner shell (that’s why shell thickness is important as well).

These 96 gallons of propane pack 8,779,392 BTU of energy, according to the EIA.

ASME (The American Society Of Mechanical Engineers) publishes a list of specifications that tell you how big a 120-gallon propane tank is. This includes everything from length, diameter (width), empty weight, shell thicknesses, leg positioning, and total height (depending on different domes that add to the height of a 120-gallon propane tank).

This ASME spec sheet is usually quite hard to find. That’s why we will list all the specs (including the full weight of the 120-gallon propane tank) for both vertical and horizontal 120-gallon propane tanks here:

120-Gallon Vertical Propane Tank Dimensions

A vertical 120-gallon propane tank is sometimes referred to as V-120. Here are the full specifications:

  • Height: 46 Inches (or 3 Feet and 10 Inches). The total height of a 120-gallon vertical propane tank without the dome is 46 inches.
  • Height With AG Dome: 53 Inches (or 4 Feet and 5 Inches). In many cases, a V-120 tank will have a dome on top of it. This dome adds additional 7 inches, resulting in a 53-inch total height of a 120-gallon vertical propane tank.
  • Diameter: 30 Inches (or 2 Feet and 6 Inches). All vertical propane tanks are shaped like a cylinder. The diameter of the 120-gallon propane tank is 30 inches.
  • Width: 30 Inches (or 2 Feet and 6 Inches). The total width of a vertical 120-gallon propane tank is 30 inches (comes from the diameter).
  • Length: 30 Inches (or 2 Feet and 6 Inches). The vertical 120-gallon propane tank is 30 inches long (also comes from the diameter).
  • Empty Weight: 260 lbs. The total empty weight of V-120 is 260 lbs.
  • Full Weight: 655 lbs. As we have mentioned above, a full 120-gallon propane tank contains 96 gallons of propane. At a 77°F temperature, 1 gallon of propane weighs 4.11 lbs. That means we are adding 96 × 4.11 = 395 lbs of propane when we are filling the cylinder to the empty weight of 250 lbs. The resulting total full weight of a 120-gallon vertical propane tank is thus 655 lbs.
  • Shell Thickness: 0.174 Inches.
  • Head Thickness: 0.173 Inches.
  • Shell Width: 29.76 Inches.

This is the size of a 120-gallon propane cylinder (vertical). Let’s have a look at horizontal 120-gallon propane tank dimensions as well:

120-Gallon Horizontal Propane Tank Dimensions

With horizontal propane tanks, the length is more important for the total footprint. Here are all specifications for a horizontal 120-gallon propane tank:

  • Length: 66 Inches (or 5 Feet and 6 Inches). As you can see, a horizontal 120-gallon propane tank is quite long (66 inches long, to be exact).
  • Diameter: 24 Inches (or 2 Feet). The diameter of the 120-gallon horizontal tank is 24 inches.
  • Width: 24 Inches (or 2 Feet). The total width of a horizontal 120-gallon propane tank is 24 inches (comes from the diameter).
  • Height: 24 Inches + Dome (or 2 Feet). A dome-less 120-gallon horizontal tank is 24 inches tall. The dome with add about 6 inches, resulting in a 30-inch total height.
  • Empty Weight: 260 – 300 lbs. The total empty weight of the horizontal tank is not standardized; an empty 120-gallon horizontal propane tank can weigh anywhere from 260 lbs to 300 lbs.
  • Full Weight: 655 – 695 lbs. As we have mentioned above, we have to add 395 lbs of propane (that’s a weight of 96 gallons of propane) to the empty weight to get the 120-gallon horizontal propane tank full weight. The resulting full weight is between 655 lbs and 695 lbs.

This has been an overview of the sizes and dimensions of both vertical and horizontal 120-gallon propane tanks. We hope that everything is quite clear now and you can plan out the footprint and the pouring pad size for these 120-gallon propane tanks.

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