With whom would you like to chat?
A LIVE Oxygen Specialist:

Customer Service:


Types of Oxygen Tanks & Oxygen Tank Sizes

There are many different types of oxygen tanks on the market, allowing for a variety of options to meet different patient uses and needs. Here are the various types of oxygen available and why they are chosen for specific patients. 

Types of Oxygen: Compressed Oxygen

Compressed oxygen tanks are what people typically think of when they think of supplemental oxygen. These tanks are one of the least expensive types of oxygen tanks and are usually covered by insurance. Though these types of oxygen tanks are quite heavy, there are smaller portable oxygen tank sizes you can fill using your larger tank. However, be aware that even a small oxygen tank can be heavy and you will need to take care to keep them upright to avoid issues with the tank.[1]

Types of Oxygen: Liquid Oxygen

When oxygen is cold enough, it turns to liquid. In its liquid state, a greater amount of oxygen can be placed in a tank while still weighing less than a compressed oxygen tank. These types of liquid oxygen tanks are usually large, but as with compressed oxygen, smaller portable oxygen tank sizes can be filled for better portability. However, there are some disadvantages to these types of oxygen units that users should be aware of. Liquid oxygen is more expensive than compressed oxygen, and it does not have as long of a shelf life as it will evaporate. When filling a small oxygen tank with liquid oxygen, users must be very careful as it is possible to get injured as a result of the incredibly cold liquid oxygen. Additionally, you are not able to take liquid oxygen tanks on a plane, making travel quite difficult.[1]

Oxygen Tank Sizes

Since both compressed and liquid oxygen tanks need to be refilled or replaced when they run out, another thing to keep in mind is the size of the different types of oxygen tanks. There are two different ways medical oxygen tank sizes are measured. The current method is to label oxygen tank sizes with M (for medical) with a number signifying the cubic feet of oxygen that each of the medical oxygen tank sizes will hold. The older method labels the oxygen tank sizes with letters, ranging from A to E, which indicates a specific size. In this categorizing system for medical oxygen tank sizes, A was the smallest unit while E was the largest. That was confusing for some users.[2]

If you are unfamiliar with the new sizing and are concerned about finding the medical oxygen tank sizes you need, most suppliers will show you the conversion of the old technique to the new sizing to ensure you get the size that is right for you. Keep in mind that while you can get large and small oxygen tank sizes, these tanks are still quite heavy and require careful handling.

Types of Portable Oxygen Tanks

You can get portable oxygen tanks for both compressed and liquid gas. These small oxygen tank units can be carried around your house, but often weigh over 10 pounds, making them hard to carry for long periods of time. When you leave your home, you will need smaller tanks, called ambulatory tanks, which usually weigh less than 10 pounds and allow for moving about more easily. You can ask your oxygen supplier about what portable oxygen tank sizes are available to you and how they are offered. Many suppliers will deliver the larger types of oxygen tanks to your home and pick up empty tanks. Some suppliers deliver pre-filled portable tanks for you, too. If not, you will still need to fill your own portable oxygen tank sizes from your larger tank. If you find that refilling your small oxygen tank becomes difficult, or that even the ambulatory tanks are too heavy, talk to your doctor about whether a portable oxygen concentrator is right for you.[3] 

Portable Oxygen Concentrators

For small, lightweight portable oxygen, a portable oxygen concentrator from Inogen may be the ideal choice. Weighing 2.8 pounds for the G4, 4.7 pounds for the G5 or 4.8 pounds for the G3, the Inogen One System Portable Oxygen Concentrators are designed for your on-the-go lifestyle with a long battery life (actual operating time depends on the model and battery type). Inogen’s oxygen concentrators also do not need to be refilled like a small oxygen tank does, as they pull oxygen from the surrounding air, so you will not have to coordinate deliveries or get rid of empty tanks. If you are trying to choose among types of oxygen tanks and want peace of mind, start by thinking about the most compatible portable oxygen concentrator depending on your oxygen needs.  Our POCs are designed for the travel needs of our active patients and their lifestyle.  As long as you have power and air, you will never run out of oxygen again. [ 1]  Inogen portable oxygen concentrators, offer you oxygen at home or away, all day, every day.

Frequently Asked Questions: Types of Oxygen Tanks

How many types of oxygen tanks are there?

There are compressed oxygen tanks and liquid oxygen tanks, each offered in a variety of sizes. Both types of tanks are available in larger sizes for more stationary use, and smaller sizes for more portable use. However, both types of tanks are heavy and most likely awkward to carry with you. Additionally, all oxygen tanks must be refilled or replaced, as they only contain a finite amount of oxygen. Oxygen concentrators are an alternative to oxygen tanks, though they are technically not tanks at all. Oxygen concentrators pull from the surrounding air, purifying and concentrating the oxygen in that air to provide medical-grade supplemental oxygen to users.

Oxygen concentrators come in stationary units, which are larger but can still be moved around a home, or portable units, which are small and easy to carry around with you.  Portable oxygen concentrators provide a safe source of oxygen-enriched air to provide medical oxygen as prescribed by a physician. Whether operating from battery power or plugged in, portable oxygen concentrators continue to produce oxygen as long as the unit has power.

What is the difference between an oxygen concentrator and an oxygen tank?

An oxygen tank and oxygen concentrator are different in a number of different ways. First, an oxygen tank contains a finite supply of oxygen, so once the tank runs out, there is no more oxygen for you to use. At that point, the tank must be refilled by a professional oxygen supplier, or it must be replaced with a new, full tank. An oxygen concentrator, on the other hand, uses the surrounding atmosphere to create purified, concentrated oxygen on demand. An oxygen concentrator does require power via an outlet or a charged battery, but as long as it has power, it will continue to produce a supply of oxygen. Additionally, while both oxygen tanks and oxygen concentrators offer portable versions, the portable tanks are still heavy and only contain a finite amount of oxygen. Portable oxygen concentrators provide a safe source of oxygen-enriched air to provide medical-grade oxygen as prescribed by a physician. Whether operating from battery power or plugged in, portable oxygen concentrators continue to produce oxygen as long as the unit has power. Additionally, many portable oxygen concentrators are lightweight and easy to carry. If you use an oxygen concentrator, it is recommended that you maintain an oxygen tank as a backup. [1,3]

How do you refill oxygen tanks?

Refilling oxygen tanks requires a certain amount of know-how and the right equipment. The safest, most reliable way to refill your oxygen tank is to contact your oxygen supply company to either trade out your tank or provide professional refill service at your home. It is recommended that a professional do this for you, as oxygen tanks can leak or explode if filled incorrectly.

That said, there are products that allow you to refill your oxygen tanks at home. Compressed oxygen home refill devices use oxygen concentrator technology, while liquid oxygen tanks use a liquid oxygen (LOX) machine. Filling your own tanks can come with risks, however, so professional refills are preferred. If you use an oxygen concentrator for your oxygen therapy, you will not need to refill anything. As long as you keep your oxygen concentrator charged, you are ready to receive your supplemental oxygen.[4]


  1. Hardavella G, Karampinis I, Frille A, Sreter K, Rousalova I. Oxygen devices and delivery systems. Breathe (Sheff). 2019 Sep;15(3):e108-e116. doi: 10.1183/20734735.0204-2019. PMID: 31777573; PMCID: PMC6876135. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6876135/
  2. Oxygen Cylinder Sizes and Info (applied-inc.com)
  3. https://www.webmd.com/lung/oxygen-tanks-how-to-choose#1
  4. https://www.wikihow.com/Fill-an-Oxygen-Tank
View all of our Inogen One Systems   See what Inogen One customers are saying  

Inogen Call For Support View Cart