How Many Gallons Are in a 30 lb Propane Tank? – Here’s the Answer!

In this article, you'll find all the necessary information on how many gallons are in a 30lb gallon tank and the comparison chart.
Rodney Nestor
Rodney Nestor
Research Writer
Rodney holds a Master’s degree in Arts and apart from working as a freelance writer, is a rather successful author of science fiction stories published in several literary read more
Last updated: September 02, 2023
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A propane tank is one of the most common sources of propane for things like generators, heaters, grills, and other mechanisms. These tanks come in different sizes, but the 30-pound is used often. It’s a good idea to understand how many gallons are in a 30 lb. propane tank.

The tanks are measured in pounds, and that is what they are filled to. But when it comes to using propane or calculating how much you need, this is assessed by understanding the gallons you have.

While these are described as a 30 lb. tank, that number refers only to the propane inside, not the tank itself. It also tells you nothing about just how much propane is actually in there. That’s where we come in. In this guide, we will share with you how many gallons you can use in these tanks and compare them to other options as well.

How Many Gallons Are in a 30 lb. Propane Tank?

How Many Gallons Are in a 30 lb Propane Tank? - Here's the Answer!
Propane weighs about 4.125 pounds per gallon, and a “30-pound tank” will hold about 7.5 gallons so that a full tank will weigh about 55 pounds.

You will find that there are several different propane tank sizes out there. What you need might depend on what you are using to power. For example, if you’re operating a large generator on propane, you need to be sure the tank and the hookups that you use are compatible.

It’s the same concept when you are operating a grill, a heater, or any other propane-fueled item. The 30 lb. propane tank can hold up to 7 gallons of propane when it is completely full. When you purchase a brand new tank or take it to get refilled, 7 gallons is what you should expect to walk away with.

That being said, you might also want to check to see if the propane company has specific details. There are companies that will only fill a tank to 80%, leaving you with about 6 gallons rather than 7. This is not always the case but certainly something to be aware of just in case.

When companies only fill to 80%, it’s a safety measure to prevent issues related to expansion or water leading to an overly full tank and causing bigger issues.

How Much Does It Weigh?

We know that this 30 lb. propane tank is going to weigh at least 30 pounds. The 30 lb. number is specifically related to the assumed weight of 7 gallons of propane within the tank. However, that number does not consider the tank materials’ weight.

Most 30 lb. propane tanks will weigh more like 50 pounds when they are filled. They will be much lighter as you use propane on your generators and other equipment. As the propane levels go down, the weight of the tank will also go down.

If you’re filling your propane tank or picking up a new one, plan for 50-55 pounds in total weight. A single gallon of propane weighs approximately 4.125 pounds. The tanks are made out of specific materials that are safe for storing and containing propane for your individual use.

Different tanks can be made from different materials, but they must all follow certain standards for the safe handling of the propane.

A tank that holds 30 pounds of propane typically weighs around 15 pounds when empty. It may be slightly more or less, depending on the tank and the brand. When you add in 30 pounds of propane, this brings the total weight to approximately 55 pounds.

Comparing a 30 lb. Propane Tank and Other Sized Tanks

How Many Gallons Are in a 30 lb Propane Tank? - Here's the Answer!
The number of gallons depends on the size, so make sure to reach out before making a purchase.

We all have different needs when it comes to the size of a propane tank. A 30 lb. propane tank is perhaps the most common size, but that doesn’t mean it’s what you are required to use. For example, if you’re operating a portable generator, you likely need a smaller and more portable propane tank as well.

There are multiple size options, from small tanks to large tanks built as a permanent tanks near a home or property. It depends on how much propane you use and your needs. For example, a home that uses propane for heat or as a gas source will likely need a permanent tank placed on its property.

If you typically just power your gas grill or a generator, a 30 lb. tank is likely the most feasible solution. Here are the most common size options for portable propane tanks.

  • 20 lb. (4.5 gallons)
  • 30 lb. (7 gallons)
  • 40 lb. (9 gallons)

The differences between them are minor but could impact your use. As you can see, the overall weight of the tank depicts how many gallons of the propane it can hold. The smaller the tank, the less propane inside. And the larger the tank, the more propane inside.

You can choose the size that works for your needs. If you only use your propane on rare occasions for small things like a small grill or small generator, you can use a 20 lb. tank. On the other hand, if you use the propane tank a lot, power large appliances, or participate in commercial grilling, you might want the larger tank.

Another difference between the various sizes is how much the tank weighs when it is full. Your 20 lb. tank will weigh about 35 pounds. We already discussed that a 30 lb. tank weighs nearly 55 pounds. And finally, a 40 lb. tank weighs around 70 pounds.

All tanks have different recommended uses, but when you’re looking at the 30 lb. tank, it’s typically used for things like camping, heaters, small appliance, and large grills.

One last thing on propane usage. It’s important to know the proper safe handling of propane tanks. Regardless of how you use your tank, understanding safety is essential to protect your items, your home, and your loved ones.

How Long Does a 30 lb. Propane Tank Last?

How long your propane tank will last will depend largely on how you use your tank. You do want to make sure you have reliable brackets and valves to make the most of your propane. If your connections are not solid and well-made, you can deal with things like leaking or overflow and lose propane from these side effects.

The last thing that you want to do is waste that $100 you spent on a 30 lb. tank by allowing the connections to waste precious propane!

The truth is that how long your propane tank lasts will largely depend on your use. For example, someone using propane daily could need a refill in less than a week. And if you only use propane here and there, your tank might last you several months.

You see, propane doesn’t go bad. Where most types of fuel have specific shelf lives that make them less viable over time, that’s not the case with propane. That means if your 30 lb. propane tank lasts you for 3 years, it’s still perfectly ok to continue using. You just want to be sure you store the tank properly when it isn’t in use.

That being said, you should be aware that a propane cylinder can possibly degrade over time.

When you purchase propane in a cylinder, you might notice a stamped date. That’s a guarantee for the cylinder and not the propane inside of it.

In addition, how long your propane lasts might depend on the BTUs being drawn from the tank and the burn rate. On average, some of the highest BTU usages will burn through a gallon of propane in approximately 1.5 hours. Again, this depends on your burn rate and the power being pulled.

Final thoughts

Now that you know how many gallons are in a 30 lb. propane tank, you can use this information to prepare yourself for propane usage and better understand how much propane you need or use. A simple tank this size holds about 7 gallons when it is filled completely but only about 6 gallons if filled according to the 80% rule.

Plan your adventures and your propane usage by understanding how much propane you have. Don’t forget to be aware of safety tips and equip yourself with the most reliable valves and connectors to preserve propane.

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