Most propane tanks weigh around 18 1/2 pounds when they are empty. Place your tank on a household scale and subtract 18 1/2 from that number. From there, you can determine how much you have left. An average size (500 sq-in) grill will use about 1 1/2 pounds of propane an hour cooking medium to high.

What happens when your propane tank is empty?

If a valve or gas line is open when the propane supply runs out, a leak can occur when the system is recharged with propane. Air and moisture that penetrates an empty tank can cause rust build-up inside the tank. Rust decreases the concentration of the odor of propane, making it more difficult to smell.

Should propane tank be completely empty?

With that said, many feel that it's safest to completely empty a propane tank when the levels inside are too low for practical use. ... Regardless of the reason, emptying out a propane tank makes it safer to both transport and store until the tank is ready to be refilled.