How much does a propane refill cost?
Last updated November 2026. Everything on this page uses typical ranges and worked examples — propane prices vary by region, season, and station, so treat the math as a way to estimate, and confirm the current rate before you go.
Refill is priced by the gallon
Most refill stations sell propane by the gallon, the same way a gas station sells gasoline. The attendant fills your tank, the meter measures how many gallons went in, and you pay for exactly that amount. If your tank already had a gallon left in it, you don't pay for that gallon again.
This is the key difference from an exchange cage, which charges one flat fee no matter how much propane was left in the tank you traded in.
How many gallons does your tank hold?
- 20 lb tank (standard grill tank): about 4.6 gallons when filled
- 30 lb tank: about 7 gallons
- 40 lb tank: about 9.4 gallons
- 100 lb tank: about 23.6 gallons
Tanks are filled to 80% of their water capacity for safety — that's why a “20 lb” tank's gallons come out to roughly 4.6 rather than a rounder number. (One gallon of propane weighs about 4.2 lb.)
A worked example (example numbers, not a quote)
Across the U.S., retail refill prices typically land in a broad range of roughly $3 to $5 per gallon in recent years — cheaper in some regions and seasons, higher in others. Using that range purely as an example:
- A completely empty 20 lb tank takes ~4.6 gallons → about $14 to $23 at $3–$5/gal.
- Topping off that same tank when it's half full takes ~2.3 gallons → about $7 to $12.
- A typical exchange fee, by comparison, commonly runs about $20 to $30 flat — and you give up whatever propane was still in your old tank.
Your station's actual price may be outside these example ranges. That's exactly why this site doesn't publish per-station prices: a price we listed last month could mislead you today.
Why prices move
Propane is tied to energy markets, so refill rates drift with wholesale prices, transportation costs, and seasonal demand — winter heating season usually pushes them up. The per-gallon price can also differ between a farm-supply store in a rural county and a rental yard in a metro area. A quick phone call to the station is the only way to get a price you can rely on, and each of our location pages lists the phone number to do exactly that.