An air compressor is a device that – as the name suggests- is used to compress and pressurize air inhaled from the atmosphere and converts power into potential energy in the process. This potential energy derived by compressing atmospheric air has a wide variety of application in various fields.

There’s no denying that an air compressor is an essential tool for a wide range of applications. Whether you are a DIY enthusiast or a professional mechanic, there is a significant possibility that you will be using an air compressor to operate different air tools. But which size of air compressor is the best one for you? It’s a common question asked by almost everyone who is newly getting into air tools.

Maybe you are a home user who needs just a moderate size air compressing machine, then buying an industrial-grade compressor will be a waste of money for you. On top of that, there will be an unnecessarily high amount of power consumption.

air compressor size

On the other hand, if you are looking to handle a professional-level workload or any kind of industrial application, buying a smaller machine will significantly hinder your work.

Even if the work is similar, then the workload creates a vast difference. Let’s say you are looking for a machine to operate automotive air tools. Still, the size of the compressor will be different depending on if you are looking for one to use in an automotive shop or you’re looking for one to use in your garage for maintenance and minor modifications of your personal car.

This is one of the most critical questions you need to ask when buying an air compressing machine, and you will find the answer right here, in this article.

So, let’s figure out what size air compressor do you need, together.

Okay, you have four basic questions in front of you that need to be answered to decide what size air compressor will be appropriate for you.

  • For what type of work will you be needing the air compressor?
  • What types of air tools will you be using?
  • How much compressed air will you be needing for our work?
  • How much air pressure will you be needing for our specific work?

What type of work will you be doing?

air compressors for vehicle mount

Compressing machines have a wide range of applications. And, different types of work require different types of tools and to be used for various periods of time. We will focus on the automotive service industry (auto body shop, auto repair, auto painting, etc.) for today’s discussion. But you can follow the same strategy to calculate an estimation for other types of tasks as well.

What types of air tools will you be using?

tools for air compressor

There is a wide variety of tools that are used in auto-related works. For instance, air hammer, air ratchet, air cut-off tool, air-powered drill, air-powered grease gun, air impact wrench, angle grinder, paint gun, etc. These are the most common types of automotive air tools.

The types of air tools and the periods of time they will be used will significantly impact the air compressor sizes.

The air tool CFM requirements are different for different tools. Some tools can operate using just a small air volume like 2.5 CFM; on the other hand, another device may need air volumes of 15-20 CFM. CFM means cubic feet per minute; this is a unit that represents the volume of air by measuring the volume delivered/consumed per minute in real-time.

Also, some air-powered tools may require a constant air supply for significant amounts of time to complete their tasks, such as a paint sprayer for auto painting, a grinder, or an orbital sander. But some can work with a small amount of air consumption. So, the air consumption will depend on which air-powered tool or tools you will be using.

So, what you should do is list all the tools you’ll be using along with their CFM requirements. Thus you can calculate an estimation of how much supply you’ll need to run the tools individually or together depending on your level of use in different circumstances like for home use or for auto body shops. But you should consider the possibility of error when calculating (20-25% is recommended) and go for a bit larger tank than you calculated. This will ensure that you have a sufficient supply even if you are working for an extended period or if there is any wastage while working.

How much compressed air will you be needing for our work?

perfect measurement of compressed air

How much air supply will be sufficient to keep your work going smoothly and without any interruption? Answering this air supply requirement question will determine the needed tank size for your home garage or your auto body and auto repair shop.

Well, there is no way to precisely answer this question because the workload or the use of power tools will not be the same every day. Sometimes there may not be that much work, and sometimes there may be a necessity of running operations for an extended period. But we can still make a premeditated estimation from practical experience.

If you are only going to be operating small tasks like inflating tires or using an impact wrench, then 5-10 gallons should be enough for you. But for a home automotive shop, approximately you should consider having a 25-30 gallon compressor to be on the safer side and to have sufficient supply even if you are working with a range of tools like a grinder or an air-powered cut-off tool for which high air supply volume is needed.

However, if you are thinking of spray painting cars, even 20 gallons will not be sufficient. If painting jobs are a crucial part of your work, we recommend considering a 60-gallon air tank.

air compressor vehicle

How much air pressure will you be needing for our specific work?

compressed air measurement

Another important specification that you must consider before buying a compressor is the pressure needed to operate your tools. PSI or pound per square inch is the unit of pressure measurement. This gives you a measure of the force applied in a unit area (in this case, square inch).

Different types of tools typically have the requirement of varying pressure levels. You have to find out the pressure range you’ll be needing to operate the different kinds of tools you’ll be using. In our experience, most of the air tools need 90 psi to function properly. Paint guns may need between 35 psi to 60 psi. The tire machines need approximately 130 psi.

Generally, the tool with the highest pressure level requirement is the one that determines the working pressure level required for the workspace. As for the other devices that have lower pressure level requirements, you can attach them with pressure reducing valves or regulators to control and set an appropriate pressure for them.

So, go through the specifications and requirements of the air tools you’ll be using in your workshop and figure out a pressure requirement for your workstation.

Keep in mind

  • You should also consider the possible pressure loss in your calculation due to the energy loss while the air travels from the compressing device to the point of use.
  • Do not unnecessarily run your compressing system at a higher pressure level. The energy consumption is proportional to the pressure level, so it will increase your cost.

More Specs

There are some other specs that you should check before deciding what size air compressor you need for your workspace.

Horsepower or HP

Horsepower is the unit of work rate or power. It measures the rate at which your motor can work.

Duty cycle

Duty cycle refers to the time your compressing machine can work with its full potential. To be more specific, the amount of time your device can provide consistent airflow and pressure.


What size air compressor is needed to paint a car? What size air compressor is suitable for truck tires? What air compressor size will be accurate for my workshop? These are some repeated questions we frequently hear from users and enthusiasts. And you should ask these questions. Buying a machine with the wrong specifications and features is a very common mistake among users. It wastes the time, money, and effort of a person.

We hope that this article will be of help in answering all your questions regarding which would be the appropriate size air compressor for your workshop; and you’ll be able to figure out on your own the deciding factors and machine specifications, such as the size of the air tank or the pressure required for specific operations when buying an air compressor.

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Hi, and welcome to Toolented. My name is Michael D. Sanders. I am a Mechanical Engineer by degree, who is a blogger by passion, and this combination of knowledge and passion is what brought Toolented to life. On my blog website, you will find necessary information about your needed automotive tools, reviews of your potential choices, and comparisons between different types of tools. To learn more click here.

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