How Much Does a 20 lb Propane Tank Refill Cost?

Published on August 4, 2026 | Written by Alec Pow
This article was researched using 15 sources. See our methodology and corrections policy.

A standard 20 lb propane cylinder supplies portable fuel for gas grills, patio heaters, camping appliances, and selected generators. In the United States, refilling a serviceable cylinder runs about $14 to $27 before tax at the cited 2026 station rates, with the final receipt driven by the gallons dispensed, the local per-gallon charge, and the amount of propane already left in the tank.

The refill bill pays for metered propane rather than another steel cylinder. A nearly empty tank may accept about 4.7 gallons, but a partially used cylinder needs less. Sales tax, station location, dispenser access, cylinder age, valve condition, and the choice between refilling and exchanging can move the amount paid at the counter.

A 20 lb propane tank refill is commonly billed per gallon. The two largest price modifiers are the amount added and the posted local rate, while an exchange uses a flat transaction price for another inspected cylinder containing a stated fuel weight.

U-Haul and Tractor Supply represent staffed, metered refill service, while Blue Rhino and AmeriGas operate cylinder exchange programs through retail cages. The U.S. Energy Information Administration tracks the regional fuel market behind local rate differences, and PHMSA sets the federal cylinder qualification rules that can determine whether a tank is accepted.

EIA’s regional propane price data show that fuel markets differ across the country, while Ferrellgas places a 20 lb exchange near $20 to $25 in its published exchange comparison. These entities connect the main parts of the purchase, including gallons dispensed, cylinder capacity, exchange fill weight, inspection status, service hours, and local fuel pricing.

How Much Does a 20 lb Propane Tank Refill Cost?

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A serviceable 20 lb propane cylinder often costs $14 to $27 (at $30 per hour, earning that amount would take about 28 to 54 minutes, before taxes) to refill before tax, based on roughly 4.7 gallons at posted rates near $3.00 to $5.77 per gallon.

Important numbers

• Entry refill estimate at $3.00 per gallon: about $14.10 for 4.7 gallons.
• Mid refill estimate at $4.00 per gallon: about $18.80 for 4.7 gallons.
• Higher posted station rate found in 2026: $5.77 per gallon, or about $27.12 for 4.7 gallons.
• Published U-Haul exchange listing: $24.95 per cylinder.
• Blue Rhino exchange fill: 15 pounds of propane rather than the cylinder’s 20 lb rated capacity.

What you’re actually buying

A 20 lb propane tank is a reusable steel pressure cylinder, not a disposable fuel can. It connects to many full-size gas grills, patio heaters, portable cooking units, and selected generators. The 20 lb name describes the intended propane weight when filled to its rated level. It does not describe the empty steel cylinder, which adds its own weight during transport.

Refilling keeps the same cylinder in service. An attendant examines the shell, collar markings, valve, and visible condition, then meters liquid propane into the tank. Exchanging works differently. The customer leaves a cylinder and takes another inspected cylinder from a cage. Buying a new tank is separate again because the buyer pays for the steel container before adding fuel. A larger home propane system also differs from a portable grill cylinder. Bulk tanks use delivery service, regulators, fixed piping, and much larger fuel orders. Readers comparing portable and bulk storage can review the separate 500 gallon propane tank costs.

The amount of propane a 20-pound cylinder can hold

A 20 lb cylinder holds about 20 pounds of propane at its rated fill. The estimated capacity is 4.7 gallons, and propane weighs near 4.2 pounds per gallon, according to the published 20 lb cylinder specifications. Multiplying 4.7 gallons by 4.2 pounds gives 19.74 pounds, which is close to the tank’s named capacity.

The cylinder is not filled with liquid to the top. Propane expands as temperature rises, so the tank requires vapor space. The overfill prevention device helps stop filling near the approved liquid level. A refill attendant also works from weight, meter readings, or both. That is why a tank labeled 20 lb does not take five unrestricted liquid gallons. The remaining propane matters too. A tank that still contains one gallon may need only about 3.7 gallons to reach its service fill. At a posted $4.00 per gallon, that top-off would be $14.80 (about 30 minutes at $30 per hour), not the $18.80 charged for 4.7 gallons. Owners of larger portable cylinders can compare the capacity math with a 100 lb propane refill.

Per-gallon refill math

Many refill locations charge about $3.00 to $4.00 per gallon, compared with exchange pricing near $5.00 to $6.00 per gallon, according to a February 2026 refill and exchange comparison. At the low end, 4.7 gallons multiplied by $3.00 equals $14.10 (about 28 minutes at $30 per hour). At $4.00, the same amount reaches $18.80. Tax can be added after the meter stops.

Local listings show why one national number cannot match every station. A Seattle refill station displayed $5.77 per gallon, which puts a 4.7-gallon fill at $27.12 before tax, based on the location’s posted Ballard refill rate. The arithmetic is 4.7 multiplied by $5.77. A partly filled tank changes that result. Adding three gallons at the same rate comes to $17.31. Metered refilling can protect the value of fuel already in the tank because the station charges for the amount added rather than assigning one flat cylinder price.

Propane added	$3.00 per gallon	$4.00 per gallon	$5.77 per gallon
2 gallons	$6.00	$8.00	$11.54
3 gallons	$9.00	$12.00	$17.31
4 gallons	$12.00	$16.00	$23.08
4.7 gallons	$14.10	$18.80	$27.12

Refill vs exchange

An exchange buys access to another cylinder and the propane inside it. Exchange grill tanks contain 15 pounds of propane under the company’s stated cylinder fill policy. A refill that brings a qualifying cylinder close to its 20 lb rating can supply about five more pounds. The difference affects both run time and the effective fuel rate.

An Elkhart station displayed a refill rate of $3.95 per gallon and an exchange amount of $24.95 in its posted local propane rates. A 4.7-gallon refill at $3.95 comes to $18.57 before tax. Using 19.74 pounds from the capacity calculation, that equals about $0.94 per pound. Dividing the $24.95 exchange amount by Blue Rhino’s 15-pound fill produces about $1.66 per pound. The exchange still has a practical role. It can solve an expired-cylinder problem, may be available after a staffed dispenser closes, and removes the need to keep the same tank. More exchange pricing context appears in the separate Blue Rhino tank pricing.

Where propane refill prices differ

Retail rates change by city and station. A Louisville location displayed $3.75 per gallon plus tax, with an exchange at $24.95, in its published Bardstown station rates. A 4.7-gallon refill at that posted rate comes to $17.63. The Seattle rate cited earlier would put the same fuel quantity at $27.12, a difference of $9.49 before tax.

Local supply costs are only one part of the spread. A store needs a dispenser, trained staff, inspection procedures, and operating hours that match the visit. Some farm stores and propane dealers meter fuel without a flat cylinder charge. Refill customers pay for the exact gallons added, with no minimum, flat fee, or purge fee, under Tractor Supply’s by-the-gallon refill policy. Calling the location before driving can confirm whether the dispenser is operating and whether an employee is available. That check matters because a lower posted rate loses value when the refill requires a separate long trip.

Cylinder age, valve condition

A low gallon rate is useful only when the cylinder passes inspection. The attendant may reject a tank with heavy corrosion, fire damage, a leaking valve, deep dents, a damaged foot ring, or unreadable markings. The manufacturing date appears on the protective collar. Requalification markings may also appear there after an approved test or examination.

Propane cylinders must be requalified within 12 years of manufacture under the federal cylinder inspection requirements. A tank outside its permitted period cannot simply be filled because the owner accepts the risk. The available paths are requalification by an approved facility, exchange, or replacement. Owners can locate approved businesses through the federal requalification facility directory. Exchange may make financial sense when an aging grill tank would otherwise need a test, valve work, and another trip. A newer cylinder with a clear stamp and clean shell is a better candidate for repeated refilling.

What you spend after refill

The meter total may not be the full trip cost. Sales tax can be added to a posted gallon rate. Driving expenses matter when the refill station sits far from the normal route. A rejected tank can create a second transaction for exchange, requalification, or a replacement cylinder. Retailers may also have different procedures for purging a brand-new cylinder, even though the cited refill policy states that no purge fee applies.

Hidden-cost callout. At the cited 2026 station rates, a full fuel charge can land near $14.10 to $27.12 before tax. An exchange listing may add $24.95 when the old cylinder cannot be filled. The combined trip can reach $39.05 to $52.07 when a buyer first expects a refill but must purchase an exchange instead, though the store would not charge both fuel transactions unless both were completed. Requalification pricing is not published in the federal safety material, so a local quote is needed before comparing that service with exchange. The calculation should include the test fee, valve work, travel, and the remaining useful life of the cylinder.

Three refill cases

Budget case. A grill owner brings in a valid tank that still holds about 1.7 gallons. The station adds three gallons at $3.75 per gallon. The fuel charge is $11.25 before tax. The low total comes from remaining propane rather than a special discount. Metered service preserves the fuel already owned.

Standard case. A nearly empty cylinder accepts 4.7 gallons at $3.95 per gallon. The refill comes to $18.57 before tax. The tank has a readable date, a working OPD valve, and no rejection issue. Higher-total case. A cylinder fails inspection after the owner reaches the store. The buyer selects the cited $24.95 exchange rather than locating a requalification shop. The main driver is cylinder condition, not the local per-gallon propane rate. These cases show why asking how much fuel remains and reading the collar date can be more useful than comparing two station signs alone.

Worked total

Take a serviceable tank that receives 4.7 gallons at a posted rate of $4.25 per gallon. A Decatur location displayed that refill rate and a $24.95 exchange amount in its published cylinder pricing. The itemized fuel math is 4 gallons at $4.25, or $17.00, plus 0.7 gallon at $4.25, or $2.98 after rounding. The refill subtotal is $19.98 before tax.

The exchange is $4.97 higher than that refill subtotal because $24.95 minus $19.98 equals $4.97. The refill can also place close to 20 pounds in the cylinder, subject to the tank and filling process, compared with the documented 15 pounds in a Blue Rhino exchange cylinder. The buyer gets a lower fuel subtotal and about five additional pounds by refilling in this example. Exchange gains value when the original cylinder is expired, damaged, or inconvenient to refill.

Who this cost makes sense for

Refilling fits owners who have a sound cylinder and access to a staffed dispenser. It works especially well when the tank still contains propane because a metered station charges for the added quantity. Frequent grill or patio-heater use can also make the larger fuel load useful, since fewer pounds are left on the table compared with a 15-pound exchange fill.

Makes sense if

• The collar date is readable and the cylinder remains within its service period.
• The shell, valve, foot ring, and protective collar appear sound.
• A refill station is on a route already being traveled.
• The tank still contains fuel that would receive no credit in an exchange.

Doesn’t make sense if

• The cylinder has expired and no approved requalification shop is nearby.
• Rust, dents, fire damage, or valve trouble may lead to rejection.
• The only dispenser is far away or closed when fuel is needed.
• An exchange solves both the fuel need and an aging-cylinder problem.

What we verified

• Checked the stated 4.7-gallon capacity and propane weight through the published refill service details.
• Confirmed that standard 20 lb cylinders from other brands can enter an exchange program under the accepted cylinder policy.
• Cross-referenced a Detroit listing showing $3.75 per gallon and a $24.95 exchange through the location’s posted refill and exchange rates.
• Verified the exchange fill weight through the company’s stated 15-pound cylinder policy cited above.

Article Highlights

• Plan on about $14 to $27 before tax for a near-empty 20 lb cylinder at the cited 2026 rates.
• Many refill stations charge by the gallon, so a partial top-off costs less than a full fill.
• A 20 lb cylinder holds about 4.7 gallons at its rated level.
• A cited $24.95 exchange contains 15 pounds under Blue Rhino’s stated fill policy.
• Check the collar date and visible condition before making a refill trip.
• Exchange can be the cleaner financial choice for an expired or rejected cylinder.

Answers to Common Questions

How many gallons go into an empty 20 lb propane tank?

A rated 20 lb cylinder holds about 4.7 gallons of propane. The amount dispensed may be lower when fuel remains inside or the attendant stops filling based on weight and safety controls.

Is it cheaper to refill or exchange a propane tank?

Refilling can be cheaper per pound of propane. The cited local examples put a near-full refill near $17.63 to $19.98, compared with an exchange at $24.95. Exchange may still make sense for an expired or damaged tank.

Can a propane station refuse my cylinder?

Yes. A station may reject a cylinder with an expired qualification, unreadable markings, corrosion, dents, fire damage, or valve trouble.

Do I lose leftover propane during an exchange?

Yes. The exchange price does not credit fuel remaining in the surrendered tank. A metered refill charges only for propane added.