What Size Air Compressor do I Need for an Impact Wrench

A pneumatic impact wrench is a common sight in tire shops and auto shops around the country. They use compressed air to loosen bolts at a much higher speed than just doing it by hand, saving a skilled mechanic tons of time while working under the hood. Garages, mechanic workshops, tire shops, break shops, basically anywhere you need to loosen a stubborn bolt or nut, you will find one. Because it uses air, you will need the right air compressor to run an impact wrench to the best of its ability. So what kind of air compressor do you need?

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How do I measure?
First, let’s take a look at how you even measure the power and size of an air compressor. There are two main units of measurement to figure out your compressor’s output, CFM and PSI. CFM stands for Cubic Feet Per Minute. This measures the mass of air flow; how much is coming out. PSI stands for Pounds Per Square Inch.

This measures the pressure; how much power the compressor is putting out. Proper amounts of air flow and pressure are needed to get an effective use out of your tools. A half-inch impact wrench, for example, usually needs around 4 or 5 CFM at 90 PSI to run properly. The capacity of an air compressor’s tank is measured in gallons, with some of the bigger ones capable of holding up to 30 gallons.

So how much of these measurements do you need to run a certain type of impact wrench? It largely depends on the size of the wrench. If you have a bigger wrench, you’ll need more CFM and PSI. It’s as simple as that. But what kinds of air compressors can deliver the goods?

Air compressors
One basic kind of air compressor is called a pancake air compressor. It is a small cylinder, which makes it easy to tote around and lightweight. Plus, it can fit easily into small spaces in your garage or shop. These types of air compressors can run an impact wrench, for a while. The only downside to the smaller tank is that you have to recharge it more often than a bigger model.

Some stationary air compressors can be as big as 30 gallons, making them downright heavy. You would need a longer hose to reach far away from one of these models. They take up more space than a pancake air compressor, so storing them is not easy. A major upside to a stationary tank like this, however, is that you can work much longer without having to charge it up again and compress more air.

The size of the tank can also help to make sure you maintain the right output of pressure and CFM for the job you are doing. For loosing up the lug nuts on a tire or two, you can handle it with a compressor tank of just 4 or 5 gallons. For bigger jobs, you may need something that is 15 gallons or so.

Other uses for an air compressor
An air compressor can be used for a variety of different DIY and professional activities. People in auto shops use them to power impact wrenches and inflate tires. People in construction use them to power tools like nail guns, staplers, drills, and different impact wrenches. People in the agricultural business use them for tractors, pumps, sprayers, and irrigation systems. They can be used to source air and for heat pump systems in heating, ventilation, and air conditioning. They can be used in oil extraction on oil rigs, packaging for foods, beverages, and pharmaceuticals, and even for inflating balloons at kids’ birthday parties.

So if you are into DIY, hobbies, or any profession that may require pneumatic tools, make sure you are getting an air compressor that can handle whatever tools you need to get the job done right.

Air Compressor for Impact Wrench
Air Compressor for Impact Wrench
Air Compressor for Impact Wrench
Air Compressor for Impact Wrench
Air Compressor for Impact Wrench


Air ToolAvg. CFM @ 90 PSIAvg. Operating PSI
Air Hammer490-100
Angle Grinder5 to 890-100
Blow Gun2 to 390-100
Brad Nailer0.570-90
Die Grinder570-90
Disc Sander2090-100
Framing Nailer2100-130
Grease Gun3120-150
Hydraulic Riveter490-100
Impact Driver (1/2")490-100
Impact Driver (3/4")790-100
Impact Driver (1")1290-100
Impact Wrench (3/8")390-100
Impact Wrench (1/2")490-100
Impact Wrench (1")1090-100
Orbital Sander6 to 970-100
Paint Spray Gun4 to 890-100
Ratchet (1/4")390-100
Ratchet (3/8")490-100
Speed Saw490-100
Staple Gun270-90
Tire Inflator2125-150

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