How to Measure the Remaining Propane

Last Updated: May 6, 2021

The only accurate way to measure the propane left in a propane tank is to weigh it. The following are the steps needed to find the amount of propane left in a propane tank and to approximate the length of time it will take to burn the propane in a given appliance.

Steps

1
Engraved on the side of the tank should be the letters TW then a number. This number is the empty tank weight. For example, the typical 5 gallon (18.9 L) propane tank might say TW 17.2. The weight of the empty tank in the example is 17.2 lbs.
2
Weigh the tank on a bathroom scale to find the total current weight. Let's say that the current weight of the tank is 24.2 lbs.^{[1]
X
Research source}

Advertisement
3
Subtract the tank weight from the total weight to find the weight of the propane. 24.2 lbs - 17.2 lbs = 7 lbs.^{[2]
X
Research source}
4
Each pound of propane contains 21,600 BTUs.^{[3]
X
Research source} Multiply the number of pounds by the number of BTUs contained in each to get the total number of BTUs remaining in the tank. 7 × 21,600 ≈ 151,000 BTUs.
5
Find the BTU output of the appliance in question. These can often be found on manufacturers web sites. For example a propane grill may burn 12,000 BTUs an hour. To find the remaining running time for the grill divide 151,000 by 12,000. 151,000 ÷ 12,000 ≈ 12.6 hours of run time.
6
For easy future reference. divide 12.6 hours by the aforementioned 7 lbs to get 1.8 hours of grill run time per pound of bathroom scale measured propane.

Community Q&A

Question

How much does a full canister of propane gas weigh?

Community Answer

Most canisters contain 20 pounds and weigh 17 pounds when completely empty. A full canister would contain 37 pounds.
Question

I have a propane cylinder that has written on it in large letters "11kg", but I have weighed the cylinder and it's 20 kg. Is there 9 kg of propane left?

Community Answer

If the "11kg" appears after "TW" (for tare weight), then you are correct. The tare weight is the weight of the tank when empty.
Question

How many pounds does it take to make a gallon?

Community Answer

You cannot convert pounds to gallons unless you know the density of the liquid. Let's assume you have a pound's worth of a solution, and this solution weighs one fourth of a pound for every quart. Convert the pounds to quarts and convert the quarts to gallons.