Propane is an important fuel source for most RVs.
So, it’s important to accurately plan out your RVs propane usage. Especially if you’re boondocking or you can’t refill your tanks in a timely fashion.
But how long does propane last in an RV? We help you answer that question (and much more).
What Are the Typical RV Propane Tank Sizes?
Before we jump into calculating your RVs propane usage, let’s first take a quick look at the different size options for RV propane tanks and the different ways to measure tank size.
When looking at a propane tank cylinder, you’ll notice the manufacturer has listed the size in terms of pounds and/or gallons:
- Measurements in pounds indicate the total weight of the cylinder when full.
- Gallon measurements are an indication of how much propane will fit inside the tank.
Typically, when you buy a tank for your RV, you’ll be looking at pounds. But knowing the gallons in your tank will help you calculate your propane usage (as we’ll get into below).
Did you know…
A “full” propane tank is only at 80% capacity. The other 20% gives the liquid propane space in which it can expand.
The two most common propane tank sizes for RVs are:
- 20 pounds: A smaller option that you can refill easily. Best for those with limited fuel use habits. It holds 4.6 gallons of propane when full.
- 30 pounds: An option that holds more propane, 7 gallons when full, but remains easy for an individual to refill and transport.
There are also 11-pound, 40-pound, and 100-pound tanks available.
Once we figure out your estimated propane usage below, you’ll know how long you’ll be able to power your appliances with your current tank size. In some cases, your current tank size may not be enough, so you may want to look into adding a second tank to your setup, carrying backup tanks, or jumping up a tank size.
How Long Does Propane Last in an RV?
Determining how long a propane tank will last for your RV depends on several factors. As you likely know, propane is not the only fuel source that your RV uses.
A large quantity of your RV’s energy use will come from electricity. But even as electricity accounts for a majority of an RV’s power supply, there may be several appliances that operate on propane.
So, how long does propane last in an RV? The answer comes from an understanding of the following factors:
- Propane tank size
- Frequency of appliance use
- The BTU rating of your propane-powered appliances
BTUs (British thermal units) are a measure of the heat content of fuels or energy sources. Luckily, we don’t need to delve deep into what a BTU is for the sake of estimating your propane usage. You simply need to know the BTU rating of each appliance that is propane-powered in your RV and that:
- One gallon of propane has 91,502 BTUs
- One pound of propane has 21,548 BTUs
With that information, you can find out the total BTUs in your tank through multiplication. After you know the total BTU capacity of your tank, you can then divide the total by the BTU usage for each propane-dependent appliance in your RV.
- Propane gallons X 91,502 = Tank BTUs
- Tank BTUs divided by total appliance BTU usage = hours before running out of propane
Tip: If you aren’t sure about the BTU usage of each appliance, check out the owner’s manual. Sometimes, that figure also appears on a tag attached to the appliance.
At this point, you have all the tools you need to figure out how long your propane will last.
But to further illustrate this concept, let’s run through an example. Our RV’s propane-powered appliances include:
- An RV refrigerator rated at 1,200 BTUs
- A water heater rated at 8,800 BTUs
- A furnace rated at 30,000 BTUs
For the sake of simplicity, we will assume that this RV uses each of those appliances equally. With that condition, those appliances (fridge, water heater, and furnace) amount to 40,000 BTUs of propane usage. Of course, your energy uses will vary depending on how many hours you spend using each appliance.
For now, let’s proceed with our simplified example using propane tanks of different sizes.
How Long Does a 20 LB Propane Tank Last in an RV?
Since your full 20 lb. tank has 4.6 gallons, first, multiply 4.6 by 91,502 to get 420,909. Then divide that figure by the total BTU usage of our appliances, which we calculated above to be 40,000 BTUs.
The answer of 420,909 divided by 40,000 comes out to 10.5. That means that we can run our appliances for 10.5 hours before running out of propane.
How Long Does a 30 LB Propane Tank Last in an RV?
A 30 lb. propane tank contains 7 gallons when full. This time, we’ll multiply 7 by 91,502 to get 640,514. Then divide that figure by our 40,000 BTUs of appliance usage.
That calculation gives us 16. That means that a 30 lb. propane tank can run our appliances for 16 hours before running out.
How Long Does a 40 LB Tank Last in an RV?
Start by multiplying 91,502 by 9.4 gallons, the amount your 40 lb. tank has when full. Your answer will be 860,119. Again, we’ll divide that figure by our 40,000 BTUs of appliance usage.
After that division, we get 21.5. That means that a 40 lb. propane tank can run our appliances for 21.5 hours before running out.
RV Propane Usage Calculator
Use the calculator below to calculate how long your propane tanks will power the appliances in your RV.
Simply enter the gallons of propane in your tank(s) and the total BTU usage of the gas appliances in your RV (you can find the BTU usage of an appliance in the owner’s manual or on the appliance itself), then click Calculate.
For reference, here’s a chart of common RV propane tank sizes and the gallons they hold when full.
|RV Propane Tank Size
|Gallons (When Full)
|11 lb. tank
|20 lb. tank
|30 lb. tank
|40 lb. tank
|100 lb. tank
How Can I Make My RV Propane Last Longer?
Conserving propane is a great way to save on energy costs and ensure you have enough fuel for your trip.
Here are a few of your best options for making your propane last longer:
- Add insulation to your RV: As with any form of heating, heat from a propane tank will be most effective when your RV has the proper insulation. Consider the areas of your RV that are most likely to allow cold air in. Adding extra insulation to doors and windows, and using an RV skirt are all great ways to prevent a waste of propane energy.
- Use your RV appliances wisely: Any appliances that are powered by propane should be used wisely. For example, if your hot water heater is propane-powered, you may want to take quicker showers (or use the campground shower). If you’re heating your RV in mild temperatures, consider operating an electric space heater instead of running your propane-powered furnace. If you run an RV fridge on propane, don’t stand at the fridge with the door open looking for food for extended periods of time. In other words, be mindful of how you use your propane-powered appliances in your motorhome. A little side tip – check out our posts How Much Propane Does an RV Fridge Use?, How Much Propane Does an RV Furnace Use, and How Much Propane Does an RV Water Heater Use? for some great tips on improving the efficiency of these appliances.
- Use a propane regulator: A propane regulator will control and regulate the amount of pressure released from the propane tank. It will ensure that your appliances get the right amount of propane they need to run efficiently.
- Choose to refill rather than exchange: No matter how careful you are about propane use, there will come a time when you run out. When that happens, you have two choices. You can exchange your tank for a new one. Or, you can refill the tank you already have. Some owners are quick to find a replacement, but refilling is not only a more cost-effective option, you can get up to 25% more propane in your tank! There is one important caveat here. Propane tanks come with an expiration date. When that date comes, refilling is no longer a safe option. Instead, you will need to find a replacement. The same is true if you notice that your tank is damaged in any way. Otherwise, refilling is a safe and frugal choice.
- Keep up-to-date with a preventative maintenance schedule: Ongoing preventative maintenance is essential to propane tank functionality. You should perform visual inspections during use and during refilling. Notice any damage that might cause your tank to malfunction, leak, or perform below its maximum capacity. Be sure to test your RV propane detector regularly to make sure it’s in good working order. Consulting a professional to ensure you’re getting the most out of your propane tank is another excellent preventative maintenance task.
How Do I Know if My RV Propane Tank Is Empty?
You can easily tell if your propane tank is empty by checking the propane tank gauge or in some cases, the propane regulator.
Don’t have a propane tank gauge? You can find one at your local home improvement store or simply order one from Amazon. They typically cost less than $20!
Check your propane tank gauge as a part of your usual visual inspections.
You can also use an RV propane regulator to monitor your tank’s levels, depending on the model. Many regulators, like the Flame King model below, will even automatically switch from one tank to another when the first tank goes empty. And the indicator on the regulator will change color when it’s time to refill your tanks.
If you don’t have a gauge, don’t worry. There is another method you can use to test your propane tank fuel level.
In lieu of a propane tank fuel gauge, you can use the hot water method. The hot water method works as follows:
- Fill a small bucket with hot water.
- Pour the hot water down the side of the tank slowly. Make sure you are pouring, not trickling the water.
- Run your hand vertically along the side of the tank. Notice any change in temperature as you do this.
- The top of the tank should be warm. That warmth indicates that there is no propane inside the tank at the point you are touching. Where the tank feels cold, there is propane inside. If you feel no change, your tank is likely empty.