how many gallon of propane in a lb?
<answer> Propane is 4.24 pounds per gallon. <context> Re: how many gallons is a 20lb propane tank?? in reply to chris smith, 02-08-2003 18:50:07 The question does not state actual capacity or rated capacity of propane. Propane is 4.24 pounds per gallon. The 20 lb rating leaves 20% of the tank empty to allow for the propane to expand when it gets warm. The tank will have water capacity (WC?) in pounds stamped on it, and I think that is 8.33 pounds per gallon.