A 1 lb (16.4 oz) propane cylinder holds about 22,200 Btu, so it lasts that figure divided by the appliance's rated input in Btu per hour. A 10,000 Btu stove burner on full runs about 2.2 hours, a 20,000 Btu two-burner stove about 1.1 hours, and a heater on 4,000 Btu about 5.5 hours. The widely quoted "about 2 hours" is correct for exactly one case: a single 10,000 Btu burner held wide open.
How much energy is in a 16.4 oz propane cylinder?#
The whole answer rests on one conversion, in three steps.
Heat content per gallon. The US Energy Information Administration gives propane as 91,452 Btu per gallon. EIA recalculates its conversion factors each year for changes in fuel quality, so the last digit moves slightly between editions.
Pounds per gallon. Liquid propane is light. NIST's reference data give saturated liquid propane a density of about 506.6 kilograms per cubic metre at 15.6 degrees C (60 degrees F). A US gallon is 3.785 litres, so a gallon weighs 1.918 kg, or 4.23 lb. Divide 91,452 by 4.23 and propane carries about 21,600 Btu per pound.
Pounds per cylinder. The "1 lb" cylinder is labelled 16.4 oz, which is 1.025 lb or 465 g. Multiply: 1.025 times 21,600 is 22,200 Btu.
The same number in metric is 23.4 megajoules, which works out to 50.3 megajoules per kilogram. That is higher than the 45.8 megajoules per kilogram the stove fuel planning guide uses for canister gas. That figure is a net calorific value, the heat a pot can receive, and it remains the one to use for litres boiled. Runtime is fuel burned divided by burn rate, and the weighing protocol below checks it against your own appliance.
Runtime by rated Btu per hour#
Rated input is the fuel an appliance burns at full output, expressed as heat per hour, and it is printed on the rating plate or in the manual. It is a rate of fuel use, not the heat that reaches your pot.
| Rated input | Same in kilowatts | Propane burned per hour | Runtime on one 16.4 oz cylinder | Typical appliance at this rating |
|---|---|---|---|---|
| 2,000 Btu per hour | 0.59 kW | 42 g | 11.1 hours | Lantern on low (about 1,900, implied) |
| 3,400 Btu per hour | 1.00 kW | 71 g | 6.5 hours | Lantern on high (implied, see below) |
| 4,000 Btu per hour | 1.17 kW | 84 g | 5.5 hours | Small radiant heater on LO |
| 5,000 Btu per hour | 1.47 kW | 105 g | 4.4 hours | One burner at half |
| 7,650 Btu per hour | 2.24 kW | 160 g | 2.9 hours | Small single burner |
| 9,000 Btu per hour | 2.64 kW | 189 g | 2.5 hours | Small radiant heater on HI |
| 10,000 Btu per hour | 2.93 kW | 210 g | 2.2 hours | Single burner on full, or one burner of a two-burner stove |
| 15,000 Btu per hour | 4.40 kW | 315 g | 1.5 hours | Two burners, one full and one at half |
| 20,000 Btu per hour | 5.86 kW | 419 g | 1.1 hours | Two-burner stove, both on full |
For any appliance not in the table the rule is one division: 22,200 divided by the rating is hours. For grams per hour, divide the rating by 47.7, which is how many Btu a gram of propane carries.
Why "about 2 hours" persists, and when it is wrong#
The two-hour figure is not invented. Common single burners, and each burner of common two-burner stoves, including both stoves in the table below, are rated at 10,000 Btu per hour, and 22,200 divided by 10,000 is 2.2. Run one on full and the cylinder empties a little after two hours, and the figure gets repeated as a property of the cylinder.
It is a property of the burner. The same cylinder on a heater's 4,000 Btu setting runs two and a half times longer, and on a two-burner stove with both burners open it runs half as long.
Cooking rarely holds full output anyway: a few minutes on high to reach the boil, then a long stretch at a fraction of it. A burner used for real meals outlasts the table, which describes a steady full burn.
If you would rather plan in water than in hours: 465 g of propane at the 18 to 37 g per litre derived in stove fuel planning boils roughly 12 to 25 litres from cold, depending on lid and wind. The stove fuel calculator does that from a menu.
What manufacturers claim, checked against the arithmetic#
Manufacturer run times are "up to" figures. The arithmetic gives a hard ceiling for each: at the rated input, the cylinder cannot supply more than 22,200 Btu. A claim above that ceiling can only be met if the appliance burns below its rating for part of the time.
| Appliance, as published | Rated input | Stated runtime per 16.4 oz or 1 lb cylinder | Ceiling from 22,200 Btu | Energy the claim needs at the rating |
|---|---|---|---|---|
| Coleman Classic two-burner, both burners on high | 20,000 Btu per hour total | "up to 1 hour" | 1.1 hours | 20,000 Btu, within the cylinder |
| Coleman Bottle Top single burner, on high | Listed as both 10,000 and 7,650 Btu per hour | "up to 2.5 hours" | 2.2 hours at 10,000, 2.9 at 7,650 | 25,000 Btu at 10,000; 19,100 at 7,650 |
| Mr. Heater Buddy MH9BX, HI | 9,000 Btu per hour | lower end of "3 to 6 hours" | 2.5 hours | 27,000 Btu, 22 percent more than the cylinder holds |
| Mr. Heater Buddy MH9BX, LO | 4,000 Btu per hour | upper end of "3 to 6 hours" | 5.5 hours | 24,000 Btu, 8 percent more |
The two-burner claim is honest. One hour at 20,000 Btu is 20,000 Btu, just under what the cylinder holds.
The single burner claim depends on which rating you believe. Coleman's own product page gives the burner as "up to 10,000 total BTUs" in the description and "Up to 7,650 total BTUs" in the specification bullets. The stated 2.5 hours is possible at 7,650 and not at 10,000.
The heater's range is rounded up. 2.5 hours on HI and 5.5 on LO are what the cylinder can supply at the stated inputs. Plan on those.
Lanterns rarely publish a Btu rating at all, so run the division backwards. Coleman describes its basic propane lantern as lasting "up to 6.5 hours on high or 11.5 hours on low" on a 16.4 oz cylinder. 22,200 divided by 6.5 is about 3,400 Btu per hour on high, and divided by 11.5 about 1,900 on low. A mantle lantern on high burns fuel at roughly a third of the rate of a stove burner, and close to a small heater on its low setting.
How cold is too cold for a 1 lb propane cylinder?#
Propane is the reason these cylinders are the cold weather fuel. Its normal boiling point is 231.1 K, about minus 42 degrees C, and until the liquid gets near that, it pushes vapour out of the cylinder on its own. The NIST-derived pressures from canister stoves in the cold make the comparison.
| Liquid temperature | Propane, gauge pressure | Isobutane, gauge pressure | n-butane, gauge pressure |
|---|---|---|---|
| 0 degrees C | 3.8 bar | 0.55 bar | 0.03 bar |
| minus 10 degrees C | 2.5 bar | 0.07 bar | none |
| minus 20 degrees C | 1.5 bar | none | none |
| minus 30 degrees C | 0.76 bar | none | none |
| minus 40 degrees C | 0.20 bar | none | none |
A cylinder of propane at minus 20 degrees C still has more gauge pressure than a butane cartridge at a mild 20 degrees C (1.1 bar).
The practical limit is not the air temperature but the liquid temperature, and the liquid cools itself. Every gram that leaves as vapour must first boil, and NIST puts propane's enthalpy of vaporization at about 19.0 kilojoules per mole near minus 7 degrees C, about 430 kilojoules per kilogram. Multiply by the burn rate in the runtime table:
- A 10,000 Btu burner on full boils 210 g an hour, which pulls about 25 watts of heat out of the cylinder.
- A two-burner stove on full, at 419 g an hour, pulls about 50 watts.
- A heater on LO pulls about 10 watts.
That heat has to come back through the steel wall from the air. In cold air the cylinder settles below air temperature, which is why it goes cold to the touch and frosts. Its pressure falls with it, the flame shrinks, and the heat you get falls while the runtime stretches. A two-burner stove on full fades first, because it pulls twice the heat out of the same small cylinder. A 20 lb tank holds 19.5 times the propane, about 433,000 Btu, and with far more liquid and wall it cools more slowly under the same burner. For warming a cylinder, the cartridge rules apply unchanged: body heat, insulation from frozen ground, a bath of cool liquid water, never a flame or a heater aimed at it.
Measure your own appliance's real Btu rating#
The rating plate gives the design maximum. A kitchen scale gives what your appliance actually burns.
- Weigh a cylinder on a kitchen scale reading to 1 g. Write the gross weight on it in marker.
- Run the appliance at a fixed setting for exactly 30 minutes, outdoors, in air above about 10 degrees C so cylinder cooling does not throttle the flow.
- Weigh it again. The loss is the propane burned in half an hour. Double it for grams per hour.
- Convert to Btu per hour by multiplying grams per hour by 47.7. A loss of 100 g in 30 minutes is 200 g an hour, or about 9,500 Btu per hour.
- Compute your runtime: 465 divided by grams per hour is hours per cylinder. At 200 g an hour, 2.3 hours.
- Repeat on the low setting you actually use for simmering or overnight heat, and note both figures on the appliance or in the kit list.
Weigh an empty cylinder of the same type once and you can also read the remaining propane in a part-used one to the gram, which is the same tare method canister stoves in the cold describes for cartridges.
Common mistakes#
Quoting runtime without a Btu rating. "A cylinder lasts two hours" describes a 10,000 Btu burner on full. For a heater on LO it is wrong by a factor of 2.5, for a two-burner stove by a factor of two in the other direction.
Adding burners without adding cylinders. Both burners of a two-burner stove on full double the burn rate and halve the runtime. A breakfast cooked on two burners on high costs a cylinder in about an hour.
Blaming an empty cylinder in the cold. A weak flame from a frosted cylinder usually means cold, not empty. Weigh it before you discard it.
Treating a lantern as harmless because it is small. A lantern on high burns about 3,400 Btu per hour, close to a heater on LO, and CPSC's warning against fuel-burning heaters and lanterns in tents while sleeping covers it. The ventilation arithmetic in the Mr. Heater Buddy in a tent guide applies to it.
Guessing the spares. Count them from the table: hours of full output you expect, divided by runtime. They belong on the car camping checklist, and camping stove types compared covers when a refillable tank is the better choice.
Frequently asked questions#
How long does a 1 lb propane tank last on a camp stove?#
About 2.2 hours for a single 10,000 Btu burner on full, and about 1.1 hours for a two-burner stove with both 10,000 Btu burners on full. The cylinder holds about 22,200 Btu, so divide by the burner's rating. Real cooking mixes full output with simmering, so a cylinder used for meals usually lasts longer than the full output figure.
How long does a 1 lb propane cylinder last in a Mr. Heater Buddy?#
About 2.5 hours on HI (9,000 Btu per hour) and about 5.5 hours on LO (4,000 Btu per hour). The manual says "up to 3 to 6 hours", which slightly exceeds what 22,200 Btu can supply at the rated inputs, so plan on the lower figures. The manual also says never to run it while sleeping.
How many Btu are in a 1 lb propane cylinder?#
About 22,200 Btu. The EIA gives propane as 91,452 Btu per gallon, and liquid propane weighs about 4.23 lb per gallon at 60 degrees F, so a pound carries about 21,600 Btu. The cylinder holds 16.4 oz (1.025 lb), giving 22,200 Btu, or 23.4 megajoules.
How long does a propane lantern run on a 16.4 oz cylinder?#
Coleman states up to 6.5 hours on high and 11.5 hours on low for its basic propane lantern. Working backwards from 22,200 Btu, that implies about 3,400 Btu per hour on high and 1,900 on low. A middle setting sits between the two.
Do 1 lb propane cylinders work in freezing weather?#
Yes, far better than butane or isobutane cartridges. Propane keeps about 3.8 bar of gauge pressure at 0 degrees C and about 1.5 bar at minus 20, where butane gives none. The limit is evaporative cooling: a burner on full pulls around 25 watts of heat out of the cylinder, so it chills, loses pressure and the flame fades well before the cylinder is empty.
How much longer does a 20 lb tank last than a 1 lb cylinder?#
A 20 lb tank holds 19.5 times the propane of a 16.4 oz cylinder, about 433,000 Btu, enough for about 43 hours of a single 10,000 Btu burner on full or about 108 hours of a heater on 4,000 Btu. With more liquid and more steel wall, it also cools more slowly than a small cylinder feeding the same burner in cold weather.
Standards, sources and further reading
- US Energy Information Administration, *British thermal units (Btu)*, Energy Explained. Heat content of propane, 1 gallon = 91,452 Btu, from the conversion factors in Appendix A of the Monthly Energy Review, which EIA recalculates each year.
- NIST Chemistry WebBook, SRD 69, thermophysical properties of propane (saturated liquid density and vapour pressure by temperature) and phase change data for propane (normal boiling point 231.1 K, enthalpy of vaporization about 19.0 kJ per mole at 266 K).
- Mr. Heater, Portable Buddy Heater Operating Instructions and Owner's Manual, model MH9BX, page 2 (input 4,000 and 9,000 Btu per hour, propane) and page 4 ("Up to 3 to 6 hours on a 1 lb. cylinder", the note on altitudes over 7,000 ft), as published on ManualsDir.
- Coleman, Classic Propane Gas Camping Stove, 2-Burner, product page, coleman.com as captured by the Internet Archive on 23 July 2025 and the Coleman Canada page. "Up to 20,000 total BTUs" and "Lasts up to 1 hour with both burners on high on one 16.4 oz. propane cylinder".
- Coleman, Bottle Top Propane Stove, product page, coleman.com as captured by the Internet Archive on 24 September 2026. "Lasts up to 2.5 hours on high", with the burner described as both "up to 10,000 total BTUs" and "Up to 7,650 total BTUs".
- Coleman, Basic Propane Lantern product description (model 2000026393), as published by Rogers Sporting Goods. "Lasts up to 6.5 hours on high or 11.5 hours on low on one 16.4-oz. propane cylinder".
How this page is made. Every number here is either a published standard, a physical constant, or arithmetic we show in full so you can check it. Read our evaluation method and editorial standards, or tell us we got something wrong.
Last reviewed and updated 30 September 2026.