Propane cylinders and propane tanks are different categories.
Propane cylinders are consumer use bottles, ranging from 4.7 gallons to 24 gallons. They are categorized by the weight of the propane that is in the bottle. So a 20lb cylinder is going to hold 4.7 gallons of propane at 4.24 pounds per gallon (4.24 x 4.7 = 19.928 pounds). There you go. Now you know.
When you register with Service Express Propane and the Text-2-Fill program you will get a chance to list the propane tanks / cylinders that you plan on filling. If you are unsure, use these charts as a reference and make a reasonable estimate. Cylinders will be verified when the driver makes the delivery.
Propane tanks are larger and generally used for home and business propane supplies. You are going to know the volume by the stamps on the tank and the fill history from your propane supplier. Remember, propane tanks are only filled to 80% their total volume to allow for expansion of the gas.
