Can you use propane in a butane stove?

No. A butane stove is built for gas at about 1 bar of pressure, and propane runs at about 7 bar. At 20 degrees C propane pushes nearly seven times harder than butane. No legal butane-style can could even hold it: at 130 degrees F propane reaches about 258 psig, and the federal ceiling for those cans is 180. The reverse, butane in a propane stove, fails in a different way.

What counts as a butane stove, and what pressure means here#

A butane stove, in the sense people search for, is a cassette stove. It is the flat, briefcase-shaped single burner sold for camping and tabletop cooking. A long 8 oz (227 g) can lies on its side in a slot, and a notch on the can lines up with a guide in the stove. Iwatani's ZA-3HP is a typical example: 12,000 Btu per hour, fuel model BU-6 only. Its manual calls it a "Portable Butane Gas Stove".

Inside every gas can, the fuel is a liquid. The gas above it pushes outward with a force set by one thing: the temperature of the liquid. That push is the vapour pressure. It does not depend on how full the can is or how big it is.

What the stove feels is gauge pressure: the vapour pressure minus the air pressure around it, about 1.013 bar at sea level. A tyre gauge reads the same way. When gauge pressure falls to zero, no gas comes out.

The stove's valve, seals and jet are sized for one gauge pressure range. The question "can I use propane?" is really "what happens when that range is multiplied by seven?"

Propane vs butane pressure, by temperature#

NIST's reference data give the vapour pressure of each pure gas. The table converts it to gauge pressure.

Two things stand out. The gap is widest exactly where people cook, from 10 to 30 degrees C. And it never closes: even at 54.4 degrees C, propane still pushes almost four times harder.

Read across a different way. n-butane reaches 7.1 bar absolute at 65 degrees C and 8.1 at 70. Propane is at 8.36 bar absolute at 20 degrees C. So a butane can would have to be heated to about 71 degrees C before it matched propane on a mild day. Iwatani tells owners to store its cans under 40 degrees C.

Why no legal butane can holds propane#

The cans a cassette stove takes are a federal container type. Iwatani's ZA-3HP manual says the fuel cylinder "must comply with UL 147B and must be marked in accordance with the U.S. Dept. of Transportation (DOT) for type 2P or 2Q fuel containers".

Those types are set out in 49 CFR 173.306(a)(3), the rule for metal aerosol-type containers of 1 litre or less. The rule ties each type to the pressure of its contents at 54.4 degrees C (130 degrees F):

The general line in the same paragraph is plain: "Pressure inside the container may not exceed 180 psig at 54.4 °C (130 °F)". Note that 180 psig is the 2Q limit. A 2P can stops at 160.

Now set the NIST figures against it. At 54.4 degrees C:

• n-butane: about 66 psig. Inside the lowest band, with room to spare.
• Isobutane: about 96 psig. Also inside the lowest band.
• Propane: about 258 psig. That is 43 percent over the 180 psig ceiling for any flammable gas in these cans.

So "propane in a butane stove" cannot mean a propane cassette from a shelf. It has to mean a different container, a 1 lb propane cylinder or a bigger tank, joined to the stove by an adapter. That is a separate decision, made by the person holding the adapter, not by anyone who tested the stove.

How much propane can a butane can carry?#

Some. Iwatani's BU-6 safety data sheet lists propane at 0 to 5 percent, as set out on the 8 oz butane canister page. Our model of a propane and n-butane mix (Raoult's law, which treats the blend as an ideal mix) puts the ceilings here:

• About 42 percent propane by mass reaches 160 psig at 130 degrees F, the DOT 2P limit.
• About 52 percent propane by mass reaches 180 psig, the DOT 2Q limit.

That is a pressure model only, and it ignores the separate rule that the can must not be liquid-full at 130 degrees F. The point it makes is simple: a little propane in a butane can is legal and normal, but a can of propane is not.

What happens if you connect propane to a butane stove#

A worked case shows where the numbers bite. Take an Iwatani ZA-3HP on a picnic table at 25 degrees C. Suppose its owner fits a 1 lb propane cylinder through a hose adapter, in place of the BU-6 can.

1. The design point. A BU-6 can at 25 degrees C is mostly n-butane at about 1.4 bar gauge, with some isobutane lifting it a little. That is the gas the stove was listed on. Its manual names BU-6 as the fuel, and the 2019 edition of the CSA standard requires makers to specify the fuel canister used for testing.
2. What arrives instead. Propane at 25 degrees C is 8.5 bar gauge (123 psi). The valve seat and seals now hold back about six times their design load.
3. The shut-off. The ZA-3HP's parts diagram labels a "Pressure Sensor Device". Its manual says the Automatic Safety Shut-off disconnects the canister "when the temperature of the main body becomes abnormally high". It adds: "In case a new canister has high inner pressure, Automatic Safety Shut-off will repeat the same function again." In other words, the stove treats high can pressure as a fault. Iwatani does not publish the trip pressure. Nothing in the manual describes it working with gas fed from an outside cylinder through an adapter.
4. The rule. The manual says "Never modify or disassemble the product" and says to use only cans marked "Iwatani Butane Fuel". An adapter is a modification of the gas path.

Walked through, the numbers say the stove would be holding back pressure it was never tested against, while the device meant to catch high pressure may never see it. Nothing here predicts a specific failure. It shows why no one can say the setup is safe.

Valves do fail at ordinary butane pressure. In 2010 Sterno recalled about 37,500 single burner butane stoves running on 8 oz canisters because the on-off valve "can fail to close completely when turned to the 'off' position". Sterno had one report of a stove failing to shut off, and no injuries. The valve is the part that propane loads hardest.

Can you use butane in a propane stove?#

Not as a stove maker's approved setup, unless the stove is sold as dual fuel. The connections do not match without an adapter. A 1 lb propane cylinder, and any propane camp stove that takes one, uses the CGA600 thread. A butane cassette uses a notch and nozzle. Adapters exist for the jump.

The problem runs the other way from the first case: too little pressure, not too much.

Cold. Whatever sits between the cylinder and the jet, a valve or a regulator (a valve that holds the burner at a steady pressure), can only lower pressure. Neither can raise it. At 5 degrees C n-butane gives 0.23 bar gauge. At 0 degrees C it gives 0.02, almost nothing. Below about minus 0.5 degrees C it gives none, while propane still has 3.7 bar. A propane stove fed butane works on a warm afternoon and fades or dies on a cold morning, the time a propane stove is usually chosen for. Canister stoves in the cold works through the same physics for screw-on canisters.

Warm. When butane does flow, the jet passes more heat than it was sized for. Gas through a fixed hole at a fixed pressure carries heat in proportion to its heat per volume, divided by the square root of its density. NIST gives 2,877.5 kJ per mole for n-butane and 2,219.2 for propane, so butane carries 30 percent more heat per volume. It is also 32 percent denser (58.1 against 44.1 g per mole), which slows the flow by the square root of that, about 13 percent. Net, by this model: about 13 percent more heat through the same jet at the same pressure. A 10,000 Btu burner would run near 11,300. That is a model of a well-regulated jet, not a measurement, but it shows the flame is no longer the one the stove was tested with.

Listing. ANSI Z21.72/CSA 11.2 covers portable camp stoves for use with propane, butane or blends of the two, outdoors only, up to 15,000 Btu per hour per burner in the 2019 edition. A stove carrying that listing is tested on the fuel its maker names. The listing does not mean any of the three.

What about adapters?#

Adapters are sold for most combinations. One retailer listing, for a CAMPINGMOON Z20, describes an adapter that lets a screw-on EN 417 canister (the isobutane and propane kind used on backpacking stoves) feed a CGA600 appliance, a propane camp stove. Its own warning: it "will leak when the gas canister is not connected to a device", so the stove end has to go on first. It is marked for outdoor use only.

An adapter changes the fitting. It does not change the gas. It cannot lower propane's 7.35 bar to suit a butane stove, and it cannot raise butane's 0.02 bar at freezing to suit a propane one. Neither stove's listing includes it. Where an adapter and the stove's manual disagree, the manual is the one that was tested.

The way to run both fuels is a stove sold for both. Gas One, for example, sells the GS-3400P as a dual fuel camp stove: "Run it on butane or connect to propane". A stove like that is sold and set up for both, and its manual sets the rules for each fuel.

Which fuel works in which stove#

Each row restates a ruling made above, with its source.

Check this before you connect anything#

Five checks, all on the stove and the can in your hands.

1. Read the rating plate or manual for the fuel named. "Butane", "propane" and "butane or propane" are three different stoves. Look for the ANSI Z21.72/CSA 11.2 listing and the fuel it lists.
2. Look at the fitting. A notch and nozzle cassette slot takes butane cassettes. A CGA600 thread takes 1 lb propane cylinders. A third fitting means a third fuel.
3. Read the can. A cassette should carry a DOT 2P or 2Q marking (US) and the contents. Iwatani's BU-6 lists propane at no more than 5 percent.
4. Check the temperature. Below about 5 degrees C, a butane can is weak in any stove. Below 0, Iwatani rules its stoves out.
5. If it needs an adapter the maker does not sell, stop. That is the point at which the stove stops being the stove that was tested.

Common mistakes#

Treating "LPG" as one gas. Propane and butane are both called liquefied petroleum gas. At 20 degrees C one is 7.35 bar and the other 1.06. They are not swaps for each other.

Reading a fitting match as a fuel match. If an adapter makes two parts fit, it has fixed the threads, nothing else.

Assuming a pressure guard covers you. The ZA-3HP's shut-off is built around a hot butane can in its own slot. An outside propane cylinder is a case it was not built for.

Buying butane for a cold trip because the adapter fits the propane stove. At 0 degrees C the butane has almost no pressure, and the regulator cannot add any. The 1 lb propane cylinder page covers the cold-weather fuel that works.

Leaving either can in a hot car. Propane goes from 7.35 bar at 20 degrees C to 17.8 at 54.4. The limits by fuel are in can you leave propane in a hot car.

Refilling a butane can from a propane tank. That puts propane in a container rated for 160 or 180 psig at 130 degrees F, where pure propane reaches about 258. Refilling and the law are covered in is it legal to refill 1 lb propane cylinders.

What this answer does not cover#

This page covers US-style cassette stoves and 1 lb propane camp stoves, on the NIST pure-gas figures and the federal can rules. It does not test or approve any adapter: none was tested, and the listings we read do not state pressure ratings. It does not cover a stove whose maker sells a conversion kit or a second inlet. That maker's manual is the authority, and it may allow what this page rules out. Real cans are blends, so their pressures fall between the columns of the table. Bulk tanks, high-output burners over 15,000 Btu per hour, and European EN 417 rules are outside it too. Carbon monoxide risk is the same with either fuel, and camp stoves under that standard are for outdoor use only. The full text of ANSI Z21.72/CSA 11.2 is paywalled and was not read, so only its published scope is cited. Before you connect anything, confirm the fuel on your own stove's plate and manual. For stove choice by season, start with camping stove types compared.

Frequently asked questions#

Can you use propane in a butane stove?#

No. At 20 degrees C propane sits at about 7.35 bar gauge and n-butane at 1.06, so propane pushes about 6.9 times harder on the stove's valve and seals. A butane stove is tested on its maker's butane can. Iwatani, for one, says to use only its own cans and never to modify the stove. An adapter that joins a propane cylinder is outside both rules.

Is propane higher pressure than butane?#

Yes, at every camping temperature. NIST data give propane 3.73 bar gauge at 0 degrees C and 7.35 at 20 degrees C. n-butane gives 0.02 and 1.06 at the same temperatures, and isobutane 0.56 and 2.01. Propane still pushes about four times harder than n-butane at 54.4 degrees C (130 degrees F): 258 psig against 66.

Why can't you buy propane in a butane can?#

Federal rules forbid it. Butane cassettes are DOT 2P or 2Q containers under 49 CFR 173.306, and their contents may not exceed 160 or 180 psig at 130 degrees F. Pure propane reaches about 258 psig at that temperature. A little propane is allowed: Iwatani's can lists 0 to 5 percent. By our model, about half propane by mass reaches the 180 psig limit.

Can you use butane in a propane stove?#

Not unless the stove maker approves it or the stove is sold as dual fuel. The fittings differ: propane stoves use the CGA600 thread. Through an adapter, butane gives too little pressure in the cold, 0.02 bar at 0 degrees C, and no valve or regulator can raise it. In warm weather, by our model, it burns about 13 percent hotter through the propane jet.

Are butane to propane adapters safe?#

No adapter is part of a stove's safety listing, so nobody has tested yours with your stove. An adapter fixes the fitting, not the pressure. One listing for an EN 417 to CGA600 adapter warns that it "will leak when the gas canister is not connected to a device" and is for outdoor use only. Follow the stove maker's manual where the two disagree.

Can a dual fuel stove use both propane and butane?#

Yes. A stove sold as dual fuel is set up by its maker for both. Gas One describes its GS-3400P as able to "Run it on butane or connect to propane". Use each fuel in the way that stove's own manual describes, not by adding adapters of your own.

Does propane work in the cold when butane does not?#

Yes. Propane boils at about minus 42 degrees C and still has 3.73 bar gauge at 0 degrees C. n-butane boils at about minus 0.5 degrees C and has almost no pressure at 0. That is why Iwatani's butane stoves are not for use below freezing, and why cold-weather car campers use a propane stove on a propane cylinder.