Single Stage Regulators
A Single Stage Regulator takes Cylinder Pressure and reduces it down to an adjustable pressure output.
For example, in the case of an Oxygen Cylinder, the cylinder pressure of up to 300 bar (4410 psi) is reduced in a single step to the output of 0-4 bar (for example).
The main advantage of a Single Stage Regulator is price. Simply put, they’re cheaper than Multi Stage Regulators.
The downside is Single Stage Regulators have a less stable output, especially at low pressure settings.
Where Single Stage Regulators are used for high output applications, it will be necessary to adjust the pressure from time to time. This is because as the cylinder pressure drops, the output pressure will
Multi Stage Regulators
A Multi Stage Regulator is a bit like having two Single Stage Regulators in one!
The first, non adjustable stage, reduces Cylinder Pressure to around 10 bar (can be up to 20 bar).

The adjustable 2nd stage is used to deliver the output pressure required by the operator.
This means when you adjust the Regulator, you are only dropping the pressure from between 10 or 20 bar to your desired output pressure. Not up to 300 bar down to desired output pressure!
Multi Stage Regulators offers two key advantages over Single Stage Regulators.
Multi Stage Regulator Output pressure is more stable.
Reducing cylinder pressure in 2 steps results in greater output pressure stability and consistency. Stable, Consistent output pressure is especially important where a very low pressure is required – very small flame torches for example.
Secondly, where high gas consumption is used, the delivery pressure is more consistent over the life of the cylinder. This is because as cylinder pressure drops, a Single Stage Regulator will gradually deliver a higher and higher gas pressure. This will necessitate regular adjustment to maintain delivery pressure.
A Multi Stage Regulator offers much more consistent output pressure because the depleting cylinder pressure has little effect on the adjustable second stage.
Conclusions
If you need your Gas Regulators to be cheap, Single Stage Regulators are likely to be your best choice.
If consistency of delivery pressure during high gas consumption applications is important to you, Multi Stage Regulators are likely to be a better choice.
If you use micro torches (Model ‘O’ or Little Torch for example), the greater outlet pressure stability of Multi Stage Regulators will be a significant advantage for you.
I hope you found this article about the difference between Single Stage and Multi Stage Regulators useful.