What is the real difference between butane, isobutane, propane and LPG?

In some ways they are almost or exactly the same.

However, there are some important differences that you need to know.

First, some short summary answers:

Propane vs Butane

Isobutane vs Butane vs PropanePropane’s biggest advantage is a lower boiling temperature, at -42° vs -0.4°C for butane.

So, propane will continue to vaporise – turn to gas – even in colder climates.

Conversely, butane vapour pressure is about ¼ that of propane, which is advantageous for some propellant applications.

Propane energy content is slightly higher by weight but lower by volume.

When are Propane & Butane Liquid or Gas?

When are Propane & Butane Liquid or Gas?
LPG (1atm)	Liquid	Vapour (Gas)
Propane	< -42°C	≥ -42°C
Butane	< -0.4°C	≥ -0.4°C

Propane, Butane & Isobutane Properties

This chart shows some of the physical property differences between the three gases.

You can refer back to the chart as we explain the importance of the numbers in the following topics…