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):

This is the upright cylinder type of propane tank.*Vertical*120-gallon propane tank.This is a torpedo-type propane tank that you put on your lawn.*Horizontal*120-gallon propane tank.

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:**(or 3 Feet and 10 Inches). The total height of a 120-gallon vertical propane tank without the dome is 46 inches.*46 Inches***Height With AG Dome:**(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.*53 Inches***Diameter:**(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.*30 Inches***Width:**(or 2 Feet and 6 Inches). The total width of a vertical 120-gallon propane tank is 30 inches (comes from the diameter).*30 Inches***Length:**(or 2 Feet and 6 Inches). The vertical 120-gallon propane tank is 30 inches long (also comes from the diameter).*30 Inches***Empty Weight:**The total empty weight of V-120 is 260 lbs.*260 lbs.***Full Weight:**As we have mentioned above, a full 120-gallon propane tank contains 96 gallons of propane. At a 77Â°F temperature, 1 gallon of propane weighs 4.11 lbs. That means we are adding 96 Ã— 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.*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:**(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).*66 Inches***Diameter:**(or 2 Feet). The diameter of the 120-gallon horizontal tank is 24 inches.*24 Inches***Width:**(or 2 Feet). The total width of a horizontal 120-gallon propane tank is 24 inches (comes from the diameter).*24 Inches***Height:**+ 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.*24 Inches***Empty Weight:**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.*260 – 300 lbs.***Full Weight:**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.*655 – 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.