What Size Air Compressor Do I Need To Work On Cars?

Air compressors are versatile machines. They have diverse uses when it comes to pneumatic tools. But the question I bumped into was, what size air compressor do I need to work on cars?

Air compressor size is determined by air pressure, tank size, and CFM. Check your air tools requirements to know what size air compressor you need.

Depending on the type of air tool you are using, the size will vary. Read further to learn how you can determine the size of air compressor you need to work on cars.

What’s An Air Compressor?

Before I put some light on how you can determine your air compressor’s size, let me tell you what an air compressor is and how it works. An air compressor is a machine that uses air to run different tools.

The air compressor’s tank fills with air, compresses it, and uses it as a power source to run the tools. Pneumatic tools can range from a nail gun to a spray painter. Different air tools require different air pressure, CFM, and tank size.

These are the primary determinants of an air compressor size.

What Size Air Compressor Do I Need To Work On Cars?

As I’ve mentioned, you can determine the size of your air compressor using three determinants. If you’re considering buying an air compressor, you should specify what tools you will use most frequently.

Do you intend to use an impact wrench or spray paint your car? These two tools will require different size air compressors. However, you can buy an air compressor that’s capable enough to use both.

Air pressure and CFM requirement are often inverse in relation. In simpler words, tools that require a higher PSI will need a lower CFM rating and vice versa.

Let’s see how you will determine the size.

Air Pressure

The Air compressor’s pressure is measured with a unit called the PSI. Abbreviation for Pounds per Square Inch is a measurement for how much pressure your tools require. Most tools will require at least 90 PSI to run.

Matching your air tool’s pressure requirement with your air compressor is one of the most important things to consider. If you don’t, your tools won’t run smoothly, and you’ll end up damaging them.

Most of the air compressors ranging from small to medium size can easily offer you 90 PSI pressure. Air compressors with a higher capacity are mostly suitable for industrial use.


CFM stands for Cubic Feet per Minute. It’s an indicator of how much volume of air your compressor can supply per minute. CFM requirements for different air tools are very diverse.

One tool may need only 0.3 CFM to whereas another might need 4 CFM. It mostly depends on the type of tool you are using.

A tool that doesn’t run continuously, like a nail gun, may require a CFM of around 2.8. An air stapler may run at 0.3 CFM, whereas a continuously running tool may require 8 or more CFM.

Note that your air tool’s required CFM is not equivalent to your air compressor’s CFM. To calculate how much CFM your machine should have, multiply your tool’s required CFM by 1.5.

Tank Size

For most tools, you won’t need a machine with a large tank. However, some tools will run more efficiently if your compressor has a larger tank capacity. Let me elaborate.

Most air tools like impact wrenches, ratchets, nail guns, etc., will run smoothly with an air compressor with a 20 or 30-gallon tank. But, if you’re operating something like a spraypainter, you’ll need a higher-capacity air compressor.

The reason behind this is, you’ll have to stop midway to refill your tank again. In the meantime, the area you’ve already painted will get dry, and when you start again after filling the tank, the paint may not be even.

With a tank of 50 to 60-gallon, you can paint your car with one refill, and the paint will be even and smooth.

Air Compressor Do I Need To Work On Cars

Things To Consider Before Running Air Tools On Cars

It’s important not to overlook a few aspects if you wish to keep your air compressor running smoothly. These concerns are not only applicable for car tools but all other air tools you operate using your air compressor.

Check If The Power Outlet Is Strong Enough

Not all circuits are strong enough to run your air compressor. How do you determine power circuit strength? It’s measured by volts.

For a small and portable air compressor, a 120-volt power outlet is enough. But if you’re operating a larger air compressor, like a 60-gallon compressor, you’ll need a 240-volt power outlet.

Even the small air compressor featuring a 30-gallon tank will draw about 15 to 20 amperes of electricity. The thing to be cautious about is, most power outlets will provide you with the electricity of 20 amperes or even less.

Experts suggest you should never use the same circuit to run multiple machines, or there’ll be a chance of damaging the circuit.

Right PSI For Each Tool

It’s not unknown to anyone that you should always use a compressor that matches your air tool’s PSI recommendation. However, not everyone realizes its true importance.

Firstly, you’re saving money. How? Not using recommended settings will damage your tools and your air compressor, no doubt in that.

So, you’re saving yourself the cost of buying a new machine and new tools.

Secondly, you can increase your air compressor and your air tool’s efficiency by using the PSI recommended by the manufacturer. The tools require a fixed PSI because it runs best in this rate. Make sure you remember that before altering the PSI.

Don’t Leave Your Compressor Unattended

Always turn off your machine and disconnect it from the power source before you leave the place. Power tools and air compressors can cause accidents if you forget to store them properly. The frequency of air compressor accidents isn’t that low.

Do Your Research

Before you go about buying any tool or any compressor available in the market, make sure you’ve invested enough time in your research. Imagine buying an air tool and then buying a compressor that can’t run your tool.

It’s suggested that you buy your tools first. Then match the tools’ requirements with the air compressor you are purchasing.

If you have multiple air tools, match the compressor with the tool with the highest requirement. You can set your air compressor’s settings lower, but you can’t increase the settings beyond its capability.

CFM Chart For Different Air Tools

Air Tool

Required CFM (Average)

Required PSI (Average)

Tire Inflator


125 to 150


3 to 4

90 to 100

Paint Spray

4 to 8

90 to 100



70 to 90

Orbital Sander

6 to 9

70 to 100

Die Grinder


70 to 90

Impact Wrench

3 to 10

90 to 100

Blow Gun

2 to 3

90 to 100

Impact Driver

4 to 12

90 to 100

Air Hammer


90 to 100

I’ve only enlisted the tools people mostly use in their garage. For precise measurement, look for your air tool’s instruction manual.

Frequently Asked Questions

Q: What size air compressor is needed to inflate tires?

Look for an air compressor that features 2 or 3 CFM with a PSI of 125 to 150. Even though a compressor with a lower PSI will work, if you want to fill up your tire without delay, it’s better to be in the higher zone.

Q: How much power does the circuit should have to run an air compressor?

If you’re operating a small and portable air compressor, a 120-volt circuit is fine. If you’re running a medium to a large air compressor, the circuit must be 240-volt.

Q: How to calculate the CFM rating for an air compressor?

Check for your air tool’s CFM requirement. Now multiply the number by 1.5. For example, if your tool requires 2 CFM to operate, the compressor should have at least 2 X 1.5 = 3 CFM capacity to run that tool.

Q: What tank size is required to use a spray paint gun?

It’s not the spray gun that requires a large tank size; it’s what you’re doing with it. If you are painting a whole vehicle, it’s better to go for a large tank size, like 50 to 60-gallon. On the contrary, if you’re only painting small areas, a small compressor with a 20 to 30-gallon tank should be enough.

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Final Verdict

You’re not the first person to wonder what size air compressor do I need to work on cars. Both your air tool and your compressor need precision to operate efficiently. The more careful you are with your tools, the longer they last, the more efficient result they offer. So, don’t hold back to ask questions to learn accurate information.

One little wrong idea about measurement, and you could end up ruining your machine and tools or, worse, hurt yourself. There’s nothing called being too careful when you’re dealing with power tools.

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