Best Air Compressor For An Impact Wrench

The impact wrench is widely used in the automotive and other sectors where it simplifies and speeds  up the removal of bolts and nuts. This device should be used in conjunction with a sufficiently sized air compressor for optimal performance – too little air pressure or too little a tank and the impact wrench won’t function. The optimal size of air compressor for any certain impact wrench is determined by a variety of criteria, including the technical parameters of both products. For the wrench to work, the attributes of both should be compatible. Below I will explain why, and how to choose the right compressor for an air impact wrench.

Scroll down to see our top picks for air compressors for impact wrenches, or use our contents menu to read more about the requirements you’re looking for.


  • CFM is the most important factor – for powering up to 1/2″ impact wrenches we recommend no less than 4 CFM
  • PSI is the next most important – 90 PSI would be the bare minimum
  • Tank size is also a big factor – we’d recommend no less than 4 gallons

Top Air Compressors for Impact Wrenches

How Much Air Pressure Does An Impact Wrench Need?

To answer this question, we’ll take a look at some common air pressures and the corresponding CFMs. We’ll start with the most basic setting: 90 PSI. This is the standard setting used by many tools. With this setting, the compressor produces about 5.7 CFMs of airflow. Next up, let’s see how these numbers change based on the air pressure settings. For example, 120 PSI. At this setting, the compressor creates 7.5 CFMs of airflow. A larger number indicates a stronger compressor. In general, a compressor producing more air pressure requires a greater supply of electricity, which leads to increased costs. However, the benefits of having a strong compressor outweigh that cost. The final thing we want to consider is the air flow. You might think that the smaller the number, the better because less air is moving through the system. But remember that the CFM measures both the volume of air and the speed at which it moves. So even though the DeWalt generates fewer CFMs at 90 PSI, it still provides a decent amount of power.

What size air compressor do I need for impact wrench?

While air pressure is significant, it is not the only factor to consider when evaluating an air compressor. You must also examine the size of the air compressor’s tank. Impact wrenches are sporadic tools. That is, unlike sandblasters or die grinders, an impact gun will not be used constantly for an extended length of time. This implies that an impact wrench may be used with a competent portable electric compressor, however a tiny pancake type would only be suitable for nail guns. Air compressor tanks are measured in gallons and available in a variety of sizes. The bigger the air compressor tank, the more air it can carry, allowing you to spend more time working and less time filling up your air tank. In short, the greater the air compressor tank size, the better. In my view, a 6-gallon air compressor with 4 CFM is the bare minimum for an impact wrench. Any lower and you will have a difficult time using it. Because I seldom use my impact wrench for extended periods of time, I’m fine with a standard 10-gallon tank. That provides me with enough air to do my tasks without spending too much or taking too long to replenish. However, someone working in a commercial environment could need a bigger tank. If you undertake professional construction work, I would consider investing in a bigger 20-gallon tank, maybe even a 30-gallon tank. In general, you’ll want to weigh cost vs capacity. Air compressors with bigger tanks may allow you to operate for longer periods of time without interruption, but they will also be much more expensive.

Top Considerations for an Air Compressor for an Impact Wrench

Continuous or Intermittent usage?

The impact wrench’s usage is important. When considering the airflow needs for the air compressor, consider how you will operate. Do you use the impact wrench in short bursts with rests, or do you need to work continuously for an extended period of time? Will the air compressor have time to recuperate between uses of the air tool? Examining such issues before selecting an air compressor for your impact wrench allows you to find the best possible combination. If the work requires continuous usage of the impact wrench, you should calculate the air compressor airflow need accordingly. Perhaps you often work on tough bolts that need the use of an impact wrench. This is something to think about while deciding on the optimal size air compressor for impact wrenches.

The impact wrench size (in inches)

Because impact wrenches come in a variety of sizes, knowing which one you’re using is essential when looking for the ideal air compressor. The breadth of the driving anvil is represented by the size of an impact wrench. Your local store may just have a few standard impact wrenches, but you can bet there is a long list of sizes. The most common diameters are 3/8-inch, 1/4-inch, and 1/2-inch. Impact wrenches with 1-inch and 3/4-inch shanks are less prevalent. See the section below for particular air compressor specs recommended for each kind of impact wrench.

Air Flow (CFM Rating) needed

The flow of air is measured in cubic feet per minute (CFM). In general, the CFM air compressor should satisfy the impact wrench’s minimum CFM rating. All that is necessary is a measurement of the air compressor’s minimum CFM rating – the tool’s CFM air compressor rating is provided by the manufacturer. Take the impact wrench’s CFM and double it by 1.5. For example, if the impact wrench has a CFM rating of 6CFM, the minimum CFM required from the air compressor is 6*1.5, which is 9CFM.

How much CFM does a 1/4 inch Impact Wrench need?

You don’t need a large amount of air pressure to use a 1/4-inch impact wrench. An air compressor delivering 1 to 1.5 CFM (cubic feet per minute, the usual measure of air pressure) would be more than enough for an impact wrench of this size. Of course, additional air pressure is an option, but it isn’t required.

How much CFM does a 3/8 inch Impact Wrench need?

More torque is required for a 3/8-inch impact wrench – almost twice as much as the 1/4. So, seek for an air compressor with a power rating of between 3 and 3.5 CFM. You could potentially get away with lower, for example, I could imagine a 2.5 CFM air compressor working out, but it would be pushing it. If you’re looking for an air compressor particularly for your 3/8-inch impact wrench, I’d suggest spending the additional money for a 3 or 3.5 CFM air compressor.

How much CFM does a 1/2 inch Impact Wrench need?

1/2-inch impact wrenches are the most popular size of wrench. In terms of size, they are also in the centre of the size chart. As a result, finding the correct air compressor for this size wrench is critical. When it comes to air pressure, you have a lot of alternatives. A 3.5 to 5 CFM air compressor will enough for a 1/2-inch impact wrench. But as a minimum I would advise going with at least a 4 CFM air compressor to play it safe.

How much CFM does a 1 inch Impact Wrench need?

Finally, there are the 1-inch impact wrenches. These are very rare and are usually only encountered on construction sites. Because of their size, these tools will need a strong air compressor to operate. I would recommend looking for an air compressor with a capacity of 9 to 10 CFM. Obviously, it will be expensive, but if you’re employing a 1-inch impact wrench, you’re presumably operating in a situation where that kind of air compressor is often required, so you are probably used to high costs!

How much PSI is needed for an impact wrench?

While some impact wrenches need 90 to 100 PSI air pressure, some require greater air pressure, even up to 140 PSI. Always check the air compressor’s PSI rating against what the impact wrench requires.

Tank Capacity (Gallons) needed

In addition to the CFM and PSI air compressor ratings, you should think about the air compressor tank capacity since convenience is important. A bigger tank allows pneumatic equipment to operate for longer periods of time, which is desirable for better output. Air compressor tanks may be as large as 80 gallons, but they can also be as little as 1 gallon. So, what is the ideal tank size for a wrench? A 6-gallon air compressor to a 20-gallon air compressor will deliver a consistent volume of air for any size air impact wrench. A bigger tank is recommended if you are utilising many impact wrenches or an impact wrench in conjunction with other air equipment. The main disadvantage of such a tank is that it is excessively heavy and cumbersome. However, if you just want to use your impact wrench on occasion, a smaller air tank may suffice. There is an easier technique to calculate the minimum tank size for an impact wrench. Once you’ve found the air compressor’s CFM rating, multiply it by 6 to obtain the tank capacity in litres. So, assuming your airflow is 9CFM, the optimal tank size is 9 * 6 = 36 litres As a result, a 10-gallon tank would be appropriate for the 9cfm impact wrench.

Duty cycle needed

An air compressor’s duty cycle is the amount of time it can run without overheating. This characteristic is stated as a percentage of the amount of time the air compressor runs in a 10-minute period. The needed duty cycle for an impact wrench that must operate constantly would be greater.

In general, a 3-gallon air compressor will not be able to power an impact wrench. Even the lightest impact wrenches need 1 to 1.5 CFM to function correctly, and most 3-gallon compressors only offer approximately 0.5 CFM. Therefore the wrench won’t have enough air flow to power it properly, and the tank will need to be refilled too often.

Will a 6 gallon air compressor run an impact wrench?

A 6-gallon air compressor can power some impact wrenches (say, up to 3/8 on average), but bigger wrenches will not perform as well. Most 1/2-inch impact wrenches demand over 5 CFM, which is more than a 6-gallon compressor normally provides. This means that when using a bigger wrench, you’ll often have to wait for the tank to refill more than you’d like.

Will a pancake air compressor be able to power an impact wrench?

Although pancake air compressors are compact and best suited for instruments like nail guns, they may also be used with an impact wrench. It is safe to use the air tool as long as the air compressor satisfies the specifications mentioned below. Porter-Cable pancake air compressors are dependable, and they work well with impact wrenches. If you use the impact wrench continually or simultaneously with other pneumatic power tools, the sole issue may be insufficient airflow.

Jeff Stelling

Jeff Stelling is an air compressor obsessive who has been working with compressors for over 25 years, since he was an apprentice engineer in the mid 90’s. He designed to offer technical guidance and buying advice for compressors.

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