Propane refill or tank exchange: which costs less
Updated October 24, 2026
A refill fills the tank you own. An exchange swaps your empty tank for one that was filled at a plant. Both get your grill running. They differ in how much propane you get, what you pay for it, and what happens to your tank.
How much propane you get
A standard grill cylinder is stamped “20 lb”, which is the weight of propane it holds when full. A refill station fills it to that limit by weight or until the overfill protection device (OPD) stops the flow, so you leave with close to 20 lb, about 4.7 gallons.
Exchange companies fill their tanks to a lower weight. Blue Rhino and AmeriGas print the net weight on the sleeve, and it is usually 15 lb. That is three quarters of a full tank.
How to compare the price
Refill stations charge by the gallon or a flat price per tank. Exchange cages charge a flat price per swap. To compare them, work out the price per pound of propane.
- Refill by the gallon: multiply the per-gallon price by 4.7, then divide by 20.
- Refill by the tank: divide the tank price by 20.
- Exchange: divide the swap price by the net weight on the sleeve, usually 15.
As a rule the refill comes out cheaper per pound, often by a third or more. Stations do not post refill prices online, so the per-gallon figure comes from the sign at the pump or a phone call. If you pay for a refill, report the price and it is shared with other readers.
When an exchange is the better choice
- Your tank is past its date. Cylinders carry a manufacture date and need requalification after 12 years. Refill stations refuse expired tanks; exchange cages take them.
- Your tank has an old valve. Tanks without an OPD valve (the triangular handwheel) cannot be refilled. Exchange cages accept them.
- Nothing else is open. Cages sit outside grocery and convenience stores with long hours, while refill needs a trained attendant on shift.
- You are starting from nothing. Buying a filled exchange tank outright is the simplest way to get a first tank.
When a refill is the better choice
- You own a good tank and want all 20 lb.
- You have a 30 lb, 40 lb or 100 lb tank, or an RV with a fixed tank. Exchange only handles 20 lb cylinders.
- You fill often. The difference per swap adds up over a season.
Where to find each
Refill happens at U-Haul stores, Tractor Supply, propane dealers, farm co-ops and travel centers. Exchange cages are at most grocery, hardware and convenience stores. The finder lists both; the filter chips switch between them.