When the 20 lb propane tank is empty, you have to refill it. How much does it cost to refill a 20 lb propane tank? This is fairly easy to calculate but you have to account for NEC guidelines when calculating the 20 lb propane tank refill cost.

Here’s the deal:

Depending on the price of propane per gallon, the cost to refill a 20 lb propane tank ranges from as **low as $7.78 and as high as $20 or more** for 1 refill.

Cost to refill a 20 lb propane tank depends on only two factors, namely:

**Cost of propane per gallon.**Propane costs per gallon are between $2 and $4. We will show you how to convert gallons of propane to lb of propane in order to adequately calculate the 20 lb propane tank refill cost.*Note:*Companies that do the refilling might charge you more for refilling; an**extra 10% to 30%**. So you might be paying anything from $2.20 to $5.20 per gallon for propane tank refilling, depending on where you refill a 20 lb propane tank.**Gallons of propane (tank capacity).**20 lb propane tank is fully refilled with only 16 lb of propane. This is done at the NEC 80% directive for safety reasons. Namely, all propane tanks can be filled only up to 80% of their capacity (hence 16 lb in 20 lb tank).

Obviously, the main problem we have with calculating how much does it cost to refill a 20 lb tank is the whole **lb vs. gallon** things. In order to know how many gallons we need to refill a 20 lb propane tank, we need to convert 16 gallons of propane (80% capacity) to gallons.

We have an entire article dedicated to how much does a gallon of propane weigh here.

To help everybody who wants to know the price of refilling a 20 lb propane tank out, we have prepared two useful resources:

**20 lb propane tank refill**Here you simply insert the price of propane per gallon and the calculator will tell you how much you are going to pay to have a 20 lb propane tank refilled.*calculator*.**20 lb refill cost**We have used prices of propane between $2 and $6 and calculated how much filling up a 20 lb propane tank would cost. You can just read the refill price on the chart.*chart*.

First of all, however, it’s quite useful to explain how to calculate the 20 lb propane refill cost:

## How To Calculate 20 lb Refill Cost

We already know that a 20 lb propane tank holds 16 lb of propane when full.

What we need to calculate first is how many gallons is this 16 lb of propane. Namely, 1 gallon of water weighs 8.34 pounds at 77Â°F. The density of propane is about 50% lower than that of water. This means that 1 gallon of propane doesn’t weigh 8.34 lb per gallon. *How much does a gallon of propane weight?*

Anywhere from 4.05 lb/gallon (at 90Â°F) to 4.20 lb/gallon (at 60Â°F). We usually take the density of propane at room temperature (77Â°F) for all propane refill calculations. At 77Â°F, the density of propane is equal to **4.11 lb/gallon**. That means that 1 gallon of propane weighs 4.11 pounds.

Here is how we calculate how many gallons of propane are in a 20 lb propane tank:

**20 lb Propane Tank = Pounds Of Propane / Propane Density**

Knowing that we need 16 lb of propane to refill a 20 lb propane tank and that the density of propane is 4.11 lb/gallon, here is how we can calculate the gallons in a 20 lb propane tank:

**20 lb Propane Tank **= 16 lb / 4.11 lb/gallon = **3.89 Gallons**

In short, you can put 3.89 gallons of propane in this tank. You will find a little bit more detailed explanation of how many gallons of propane are in a 20 lb propane tank here.

Now that we know that, we just have to calculate how many dollars it cost us to fill our tank with 3.89 gallons of propane. We simply need to multiply the required gallons of propane with the cost of propane per gallon like this:

**Cost To Refill 20 lb Propane Tank = 3.89 Gallons Of Propane Ã— Price Of Propane Per Gallon**

Let’s say that the price of propane per gallon at your location is $3.20. Here is how much you will pay to have a 20 lb propane tank refilled:

**Cost To Refill 20 lb Propane Tank **= 3.89 Gallons Ã— $3.20 Per Gallon =** $12.45**

This is how you can simply calculate that you will need to pay $12.45 for a 20 lb propane tank refill.

Now, the price of propane per gallon can vary quite a bit. That’s why it’s best to use the 20 lb propane tank refill cost calculator that automatically determines the cost of refill based on the propane per gallon cost. Below the calculator, you will also find a chart when we have calculated how much filling a 20-pound propane tank will cost if the prices of propane per gallon and between $2 and $6:

## 20 lb Propane Tank Refill Cost Calculator

Here you simply insert the price of propane per gallon in your area, and you will get how many dollars it will cost you to refill a 20 lb propane tank:

It’s quite easy to calculate the 20 lb propane tank refill cost with this calculator. Let’s say that you have a high propane cost in your area – $3.90 per gallon. You just slide the slider to ‘3.90’ and the calculator will give you the result:

It will cost **$15.17** to refill your 20 lb propane tank at *$3.90* per gallon of propane cost.

Here is a full table of 20 lb refill costs if the prices of propane are as low as $2 per gallon to as high as $6 per gallon:

## 20 lb Refill Cost Chart

Cost Of Propane Per Gallon: |
20 lb Refill Cost: |

$2.00 Per Gallon | $7.78 |

$2.10 Per Gallon | $8.17 |

$2.20 Per Gallon | $8.56 |

$2.30 Per Gallon | $8.95 |

$2.40 Per Gallon | $9.34 |

$2.50 Per Gallon | $9.73 |

$2.60 Per Gallon | $10.11 |

$2.70 Per Gallon | $10.50 |

$2.80 Per Gallon | $10.89 |

$2.90 Per Gallon | $11.28 |

$3.00 Per Gallon | $11.67 |

$3.10 Per Gallon | $12.06 |

$3.20 Per Gallon | $12.45 |

$3.30 Per Gallon | $12.84 |

$3.40 Per Gallon | $13.23 |

$3.50 Per Gallon | $13.62 |

$3.60 Per Gallon | $14.00 |

$3.70 Per Gallon | $14.39 |

$3.80 Per Gallon | $14.78 |

$3.90 Per Gallon | $15.17 |

$4.00 Per Gallon | $15.56 |

$4.10 Per Gallon | $15.95 |

$4.20 Per Gallon | $16.34 |

$4.30 Per Gallon | $16.73 |

$4.40 Per Gallon | $17.12 |

$4.50 Per Gallon | $17.51 |

$4.60 Per Gallon | $17.89 |

$4.70 Per Gallon | $18.28 |

$4.80 Per Gallon | $18.67 |

$4.90 Per Gallon | $19.06 |

$5.00 Per Gallon | $19.45 |

$5.10 Per Gallon | $19.84 |

$5.20 Per Gallon | $20.23 |

$5.30 Per Gallon | $20.62 |

$5.40 Per Gallon | $21.01 |

$5.50 Per Gallon | $21.40 |

$5.60 Per Gallon | $21.78 |

$5.70 Per Gallon | $22.17 |

$5.80 Per Gallon | $22.56 |

$5.90 Per Gallon | $22.95 |

$6.00 Per Gallon | $23.34 |

As you can see, the cost of propane determines how much you are going to pay for a 20 lb propane tank refill. It can be below $10 if the propane cost per gallon is below $2.60 or more than $20 if your propane cost per gallon is $5.20 or higher.

Hopefully, you now have enough information to calculate the refill cost of the 20 lb propane tank yourself. If you have any questions and would like our help, just use the comments below and we will help you out.