Butane and propane are both popular fuel types for camping stoves and other equipment. Although they’re both LPGs, their BTU ratings are different.
Propane’s BTU rating is 21,594 per pound while butane’s is 21,300 per pound. Propane is a denser LPG and has more energy per ounce than butane. Propane’s BTU rating per gallon is 91,502, while butane’s is 107,000.
A fuel’s BTU rating refers to how long it takes to heat 1 lb of water, and the higher the rating, the more fuel-efficient it generally is.
However, that’s not the only factor to consider when choosing between propane and butane.
Butane and Propane: BTU Ratings Compared
Below is a table comparing the BTU rating of propane and butane:
| Propane BTU Rating | Butane BTU Rating | |
|---|---|---|
| BTU Rating Per Gallon | 91,502 | 107,000 |
| BTU Rating Per Pound | 21,594 | 21,300 |
| 8oz Canister (when filled 80%) | 8,520 | |
| 16oz Canister (when filled 80%) | 17,040 | |
| 1 lb Tank (when filled 80%) | 17,276 | |
| 20 lb Tank (when filled 80%) | 345,504 | |
| 30 lb Tank (when filled 80%) | 518,280 | |
| 40 lb Tank (when filled 80%) | 691,008 |
As you can see from the table above, the rating differences between butane and propane are very small and for regular camping uses such as cooking you're highly unlikely to notice any difference at all.
However, you can’t compare the BTU rating of a 20lb propane tank with the same size butane tank because butane containers are usually much smaller.
If you’re planning a long trip off the grid, propane is better as 30 lb tanks last longer than a few butane canisters. Propane also comes in refillable tanks whereas butane is almost always sold in disposable canisters.
In addition to different BTU ratings, both gases burn at different temperatures with propane burning slightly hotter and the flame transferring heat more efficiently when compared to butane. This can have a big impact in applications like welding, but the impact is hardly noticeable when used in appliances like camp stoves.
How To Calculate Your Appliance’s Fuel Usage with Butane or Propane
If you want to check how efficiently your camping or RV appliance works, you’ll need its BTU rating and that of the fuel you use.
Then, you’ll need to do a few simple calculations to check how much butane or propane you typically use per hour.
Here’s how to do it:
1. Obtain your appliance’s BTU rating from your user manual or check online by searching for your appliance’s model number and name.
Remember that this is the rating when the appliance runs at full capacity. For instance, if your camping heater runs on high or you use both plates on your stove at the same time at maximum heat.
Try and figure out what capacity you use your appliance (if, for example, your camping stove’s BTU rating is 20,000 but you normally only use 1 plate at a time, you usage will be around 10,000 BTUs).
2. Check your butane canister or propane tank’s capacity.
Any responsible seller will only fill the canister to 80% capacity as a safety measure and to accommodate any gas expansion, so you should work out its capacity at 80% (e.g. an 8 oz butane canister will typically only have 6.4 oz when full).
3. If your appliance runs on propane, multiply its BTU rating of 91,502 by how many gallons of propane are in the tank. Then, divide your answer by the BTU rating of your appliance.
Eg. a 30 lb propane tank has 7.1 gallons of propane in it. This gives you a total of 649,664 BTUs in your tank.
For our 10,000 BTU single stove we would do 649,664 / 10,000 = 64.9 hours (2.7 days) of usage
4. If your appliance uses butane, multiply its BTU rating of 21,300 by the number of pounds of butane you have. Then, divide the answer by the appliance BTU rating.
For example a standard 8 oz butane can contains 6.4 oz of butane (0.4 lbs). This gives a total of 8,520 btus.
My single burner butane stove works at 8,500 BTUs so it will run for around an hour on a single can.
8520 / 8,500 = 1 hour 15 seconds
