What Size Air Compressor Do I Need For Impact Wrench?

What Size Air Compressor Do I Need For Impact Wrench

The compressor’s size is not the ultimate factor that determines the impact wrench’s power. However, you still need a minimum size that is compatible with the impact wrench.

So, what size air compressor do I need for an impact wrench? I will answer this question in the post and provide helpful information on the air compressor.

Continue reading, and I will show you!

Popular Airflow Units

The air compressor size is not measured by its diameter, but commonly the PSI (air pressure) the machine can generate. Another critical factor is the air compressors’ CFM (airflow).

The higher these two measurements, the higher the compressor’s capacity.

Each air compressor has a unique PSI and CFM for every product line. Therefore you need to choose a suitable capacity for your impact wrench.

A larger impact wrench requires more powerful air compressors to work with.

Before I discuss the ways to choose a suitable size, let’s first walk through some popular impact wrench types.

¼ Inches

The ¼ inches impact wrenches don’t require much air pressure to operate. Air compressors between 1 and 1.5 CFM in capacity will work well with this category.

Of course, the more powerful air compressors are still compatible with this impact wrench size, but you will end up wasting its power.

⅜ Inches

Though ⅜ inches impact wrenches are still relatively small, they demand a little more air pressure to function. The air compressor must be twice as powerful as the ¼ inches wrenches.

The suitable compressor size should be between 3 and  3.5 CFM in this case.

A little bit weaker compressors are still sufficient, but this power range offers optimal functionality.

½ Inches

½ inches are the most common size for the impact wrenches, which fall into the medium-size category. An air compressor with around 3.5 to 5.5 CFM will work fine for this size.

However, you should use a compressor with more than 4 CFM power to ensure a safe and optimal operation.

If possible, a 5-CFM will be the optimal option, providing high functionality and safety.

1 Inch

1 inch is among the largest sizes for impact wrenches.

Due to their large sizes, the impact wrenches of this kind are rarely installed for regular households, which are more prevalent for construction sites.

For an impact wrench of this size, you will need an extremely powerful compressor to operate, which should have at least 9 or 10 CFM.

Such a powerful air compressor will be more costly than the lower settings.

​Read more: How To Increase CFM On Air Compressor?

Medium-size Impact Wrench

What Size Air Compressor Do I Need for an Impact Wrench?

The size of the air compressor is correlated with the impact wrench’s size. So, a larger impact wrench requires a more powerful compressor to work with.

The most common impact wrench size is ½ inches, which works with a 4 CFM to 5 CFM (around 90 PSI) air compressor.

You should choose the air compressor’s size accordingly for larger or smaller sizes.

In the section above, I have covered the most popular impact wrench sizes and their suitable compressor size.

However, the number is not always definite, and there are some other factors you should consider before choosing.

Besides the impact wrench’s sizes, the surrounding space, workplace condition, and type of project also determine the air compressor’s sizes.

I will explain these details further in the following sections. Now let’s first learn how to calculate the needed air and compressor size for your impact wrench.

The Air Tank

How To Calculate Air Compressor Tank Size For Your Impact Wrench?

A proper air compressor CFM should be compatible with your impact wrench’s CFM rating, which is written in its product requirements.

Therefore, you first have to look at the requirements for your impact wrench.

Most manufacturers will include the recommended minimal CFM on their product’s labels. You can calculate the suitable air compressor’s size by multiplying this figure by 1.5.

Your impact wrench may have a minimum recommended CFM of 5 CFM. You can multiply this number by 1.5 and get an optimal air compressor size of 7.5 CFM.

This means that your air compressor should have at least 7.5 CFM in power to operate well with the impact wrench.

Air Tank

After calculating the minimal CFM, you should consider the proper size of your air compressor’s tank.

Commonly, an air compressor with a larger air tank can supply higher power for the impact wrenches.

This task is really easy. All you have to do is multiply the minimal CFM required by your impact wrench by 6. Take the previous 5 CFM requirements, for example.

You can multiply it by 6 to get a recommended tank size of 30 CFM.

So just by using the impact wrench’s minimal CFM requirement, you can calculate both the air compressor’s airflow and tank’s size that works optimally with it.

Factors to Help You Decide Air Compressor’s Size You Need

Besides the impact wrench’s requirements, the surrounding environment and project’s type can also decide the optimal air compressor sizes.

If you want to achieve optimal functionality, don’t skip these little details.

Project’s Type

You will need a very powerful air compressor to operate the impact wrench installed for the large construction sites.

Most air compressors in these projects should have at least 10 CFM or more in power.

Meanwhile, regular households or small businesses use a much smaller impact wrench, thus reducing the air compressor’s size significantly.

If your business requires high torques, consider installing a 2-stage air compressor. A device of this kind can deliver up to 175 PSI, while a single compressor can only produce 125 PSI.


For working sites with large space, you will need a bigger air compressor to operate the large impact wrench.

Meanwhile, a small space requires much smaller air compressors’ with around 4-5 CFM.

However, air compressors with large sizes are not always more powerful and deliver a higher airflow.

It also depends on the type and qualities of the device. Therefore you should check its CFM carefully before purchasing.

High Torque Impact Wrench

Is The Air Compressor’s Size Important?

The tank size doesn’t always accurately indicate the air output of a compressor.

There are many premium air compressors that can produce a significant airflow capacity despite their small tank and lightweight.

Therefore, you cannot know if a compressor is powerful or not just by looking at its size solely.

There are four factors you should consider which are Power rating, CFM, PSI, and finally, the tank size.

If you need more in-depth information on this question, consider watching this video to learn more!

Final Thoughts

The larger the impact wrench, the more powerful your air compressor needs to be.

However, you should not look at the compressor’s tank size solely to determine its power.

You can use the impact wrench’s minimal CFM requirement to accurately calculate the air compressor’s tank size and its air output.

Also, don’t forget to consider the outer factors like the project’s types and space.

I hope that the answers provided in this post can satisfy you.

Thank you for your time!

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