How To Tell How Much Propane Is Left In A Tank

Getting ready to grill but not sure if you have enough propane? In this article you’ll learn 3 simple ways to tell how much propane is left in a tank.

A propane tank gauge hooked up to a tank with the readout showing about 3/4 of the tank is full.
Looks like I’ve got plenty of gas to cook with!

It’s every griller’s worst nightmare. You’re right in the middle of a BBQ and you’ve got half-cooked chicken breast and steaks sitting on the grill when suddenly the flames die out and you realize you’re out of gas.

If only there was a way to know you were running low on fuel before you started cooking.

Well there are actually 3 ways to check how much propane is in a tank. Master there simple techniques and you’ll never have to worry about running out of gas again.

  • Weight the tank
  • Use warm water
  • Use a propane gauge

Let’s take a closer look at each method.

Weigh The Tank

One way to estimate the level of propane in your tank is by weight. For an extremely rough estimation you can simply lift the tank and see how it feels. If you’ve grilled long enough you develop a feel for the weight of an empty tank vs one that still has gas to give.

But that’s a pretty unscientific approach. A much more accurate method would be to actually weigh the tank to determine how much propane is inside.

A standard propane tank like the ones you use for grilling weighs about 17 pounds when empty. To be more exact, the tank itself weighs 16.6 pounds and most tanks will have that number stamped somewhere on the collar that protects the valve. It might also indicate TW or tare weight, which is simply the accepted weight of a container when empty.

So now that you know the tank’s tare weight, you can easily calculate the amount of propane inside by subtracting the tare weight from the tank’s total weight.

For example, let’s say you weigh the tank and the scale says it weighs 25 pounds. The tare weight is 17 pounds which means you have about 8 pounds of propane left.

Note – some grills have a built in scale that helps you estimate how much propane is left in a tank. Below is a picture of the scale on my ten year old Weber Genesis.

A propane tank on a tank scale with the indicator reading half full.
Looks like I’ve got about half a tank left.

It’s not perfect, but it does help you know when the tank is getting low and ready for a refill.

Use Warm Water

This is a really neat trick and all you need is a cup of hot water. The water doesn’t need to be boiling hot, just hot water from the tap will do nicely.

Here’s how to tell how much propane is left in a tank using nothing but a glass of water.

  • Fill a cup of hot water from the tap
  • Pour the hot water down the side of the tank
  • Run your hand down the side of your tank until you feel a cool spot

The reason this method works is because the propane in the tank absorbs the heat from the hot water faster than the air in the empty part of the tank. The empty part of the tank will remain warm to the touch while the part that still contains propane will cool quickly.

As you run your hand down the side of the tank you’ll notice a significant difference when you get to the section that has propane in it.

This method isn’t exact, but it will give you a good estimate of how much propane you have left so you’ll know if you have enough to cook or you need to get more.

The guys from the “FIX IT Home Improvement Channel” made a short video demonstrating how to use this method.

Use A Fuel Gauge

The most accurate way to measure the amount of propane left in a tank is to use a gauge, Propane tank gauges come in three different types and you can find them in a hardware store or on Amazon.

An inline pressure gauge installs in between the valve on the propane tank and the gas line that feeds into the grill. Just screw it into place and when you open the tank’s valve the gauge will tell you how much propane is left.

An analog propane scale is basically just a miniature scale with a hook attached. Simply loop the hook through the tank’s handle, pick it up, and read the scale to see how much propane is left.

Electronic propane tank sensors attach to the bottom of your tank via a strong magnet. They use ultrasound to accurately measure the amount of propane left in your tank and then send the data directly to an app on your smartphone so you can always know exactly how much gas you have left.

The only type of propane gauge I’ve tried myself is the inline gauge. It comes in handy when your tank is inside the grill itself or otherwise hard to reach or pick up. Otherwise I normally just pick up the canister to estimate how much propane inside.

How Long Does A Propane Tank Last?

Some people will tell you you can tell how much propane is left in a tank by tracking how much cooking you do with it. To do this you’d need to keep some kind of log to track how long you cook with the tank.

I think that’s crazy. When I’m grilling, I’m focused on the food (and maybe the cocktail I’m drinking with it). Keeping a log of every minute the propane is turned on just isn’t realistic.

It’s also bound to be wildly inaccurate because there are so many variables that could affect the total cooking time of a tank.

A standard 20 pound propane tank should get you somewhere between 15 and 20 hours of cooking time.

But that’s just a rough average. Actual cooking time will depend on a number of factors including:

  • How much propane the tank started with. Was it completely full or only “kind of” full like the ones you get at an exchange station. Their tanks could give you as much as 25 percent less cooking time!
  • The size of your grill and how many BTUs your particular grill uses.
  • Whether you cook on low or high heat.
  • Your location. If you live in a high altitude area you’ll likely need to preheat and cook for a longer amount of time

For these reasons I don’t think using cook time will ever give you an accurate estimate of how much propane you have left. You’d be much better off just using one of the other methods discussed above.