How to Measure Your Camping Fuel Canisters: 2 Methods

If you’ve ever been out camping or backpacking, you know how essential a reliable stove is. Stoves that run on fuel canisters are incredibly popular—they’re lightweight, easy to use, and bring water to a boil in no time. However, there’s one small challenge: how do you know how much fuel is left in a partially used canister?

The last thing you want is to be miles from civilization, with a pot of food that refuses to cook because your fuel ran out. Luckily, there are two simple ways to check your fuel levels before heading out. In this guide, we’ll walk you through both methods—using a scale for precise measurement and using water for an easy, visual check.

Method 1: Weighing the Canister (Most Accurate Way)

If you want an exact measurement of how much fuel remains, weighing your canister is the best method. While you wouldn’t carry a kitchen scale into the wilderness, this technique is great for checking fuel levels before you leave home.

What You’ll Need:

• A partially used fuel canister
• An empty fuel canister of the same size
• A digital kitchen scale

Steps to Follow:

Step 1: Weigh an empty canister

If you already have an empty canister, place it on the scale and write down its weight. If not, check the fuel canister’s label. Most will list both the net fuel weight (the fuel inside) and the gross weight (the total weight when full). Simply subtract the net fuel weight from the gross weight to find the empty canister’s weight.

Step 2: Weigh the partially used canister

Place your used canister on the scale and note the number.
Calculate the remaining fuel – Subtract the empty canister’s weight from the partially used canister’s weight. The result is the amount of fuel left.

Step 3: Estimate fuel levels

Compare this remaining weight to the net fuel weight listed on the canister. If your canister originally held 230g of fuel and you now have 115g left, then you’re at about half a tank.

Why This Works:

This method is highly accurate because it directly measures the remaining fuel. It’s perfect for planning a trip, ensuring you pack enough canisters to last the whole adventure.

Method 2: The Water Float Test (Great for On-the-Go Checks)

If you’re already outdoors and need a quick estimate of how much fuel remains, the water float test is your best bet. This method lets you visually gauge fuel levels without special tools—just a pot of water and your canister.

What You’ll Need:

• A partially used fuel canister
• An empty canister of the same size
• A full canister of the same size
• A cooking pot filled with water
• A permanent marker (optional)

Steps to Follow:

Step 1: Fill a pot halfway with water

The pot should be large enough to let the fuel canister float freely.

Step 2: Float the full canister

Gently place a full canister in the water, tilting it slightly to let any trapped air escape. Note where the waterline touches the canister and mark it with a permanent marker.

Step 3: Float the empty canister

Repeat the process with an empty canister. Again, mark the waterline.
Mark your used canister – Transfer the markings from the full and empty canisters onto your partially used one.

Step 4: Check the fuel level

Place the partially used canister in the water and mark where the waterline lands. Compare this with the full and empty markings to estimate how much fuel remains.

Alternative: Some Canisters Have Built-in Gauges

Certain brands, like MSR, print fuel level indicators directly on the side of their canisters. Instead of marking the canister yourself, simply float it in water and use the built-in guide to see how much fuel is left.

Why This Works:

This method is easy and requires no extra equipment, making it perfect for checking fuel levels in the field. While not as precise as weighing the canister, it gives you a quick visual estimate so you’re not caught off guard.

Which Method Should You Use?

• For precise measurements → Use the weighing method at home before your trip.
• For quick on-the-go checks → Use the water float test while camping.
• For convenience → Check if your canister has a built-in fuel gauge.

Conclusion

Knowing how much fuel is left in a canister can save your trip from a cold, uncooked meal. Whether you prefer the accuracy of weighing the canister or the convenience of the water float test, both methods help ensure you pack enough fuel for your adventure.