How to Measure How Much Fuel is Left in a Canister | REI Coop
In the first method, you'll use a kitchen scale to weigh a partially used canister and a completely empty one, then subtract the empty weight from the partially used weight to determine how much fuel remains (by grams or ounces). In the second method, you'll float the canister in a pot of water. Where the waterline lands on the canister is ...