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  • Mon. Sep 25th, 2023

How Many CFM Does An Impact Wrench Need

BySomiala Obgorto

Oct 19, 2022

Any prior experience with air tools will tell you that you need to know the precise PSI and CFM for the optimal performance of the tool. The case of pneumatic impact wrenches is the same. Hence, the need for every user to find out how many CFM an impact wrench needs arises.


Connecting the impact wrench to an air compressor and turning the pressure to the max will only end badly. The perfect amount of CFM will make sure that you get done with your work without hitting any hurdles. Not to mention, when it comes to impact wrenches the right CFM will also enhance the performance of the tool.


If there is one thing I have learnt, it is never to take any detail lightly when it comes to power tools. Therefore, I have shared the required amount of CFM needed for an impact wrench down below. Read this article thoroughly before picking up your pneumatic impact wrench.

How Many CFM Does An Impact Wrench Need?

Every model of impact wrench needs a different CFM. The detail below will help you understand the CFM required for your model.

What Does CFM Mean?

The term CFM stands for cubic feet per minute. It denotes the amount of airflow rate that any tool needs in order to function perfectly. Similar to other air tools, pneumatic impact wrenches also need a specific amount of CFM to operate. If you want your impact wrench to deliver the best results, then figure out the CFM it needs to run.

How Many CFM For An Impact Wrench

When it comes to impact wrenches and CFM, you can not put all of the models in a single category. Every model present on the market needs has its own separate CFM requirements. The general range is between 1 to 10 CFM, the former being the lowest and the latter being the highest for impact wrenches. The smaller models of impact wrenches need less CFM than the larger and professional-grade models.

Ideal CFM According To The Size Of Impact Wrench

As we know every model needs a different CFM to run, let’s talk about the specific needs of different models.

For ¼ Inch Impact Wrench

A ¼ inch impact wrench is the smallest size present on the market. Being the smallest, this size does not require high air pressure to function. Therefore, hooking it to an air compressor that offers 1 CFM or 1.5 CFM will get the tool to function smoothly. Connecting it to a 1.5 CFM air compressor will give you more pressure. So, if you need to work on a project that calls for more pressure, opt for the air compressor that offers 1.5 CFM.

For ⅜ Inch Impact Wrench

A ⅜ inch wide impact wrench needs a slightly more CFM than a ¼ inch one. As it is bigger, it requires more power to run. So, an air compressor that provides 2.5 CFM to 3.5 CFM will be perfect for a ⅜ inch impact wrench.

For ½ Inch Impact Wrench

A ½ inch model comes with a powerful motor and needs way more CFM to start functioning than the smaller impact wrenches. Anything less than 4 CFM will not fo for a ½ inch air impact wrench. You can also hook it to an air compressor that offers 5 CFM, but not more than this.

For 1-Inch Impact Wrench

Every owner of a 1-inch impact wrench needs to take out the big guns, as low CFM does not do anything for these models. They need a minimum of 9 CFM to start operating. An airflow lower than this will not work on these impact wrenches. You can also get your hands on air compressors that offer 10 CFM for your 1-inch impact wrench.

How To Figure Out The Required CFM For Your Impact Wrench?

Running pneumatic impact wrenches is no joke, so you need to figure out the precise requirements of your tool. There are two ways that you can play this, either take the word of every random on the internet or do the calculations for yourself. The points presented above apply to most models of impact wrenches. But from my experience, it is better if you make take the specific needs of your tools into consideration. A simple way of finding out the CFM needs of your impact wrench is to know the CFM ratings of your tool. Every tool comes with its own CFM ratings. Take that number and multiply it by 1.5 and you will know the exact amount of CFM that your air impact wrench needs. To play it safe, I’d recommend going a number higher than the calculated amount.


You can not run an impact wrench without knowing how much CFM it needs. The tool will either not function at all, or even if it does, there is no way it will deliver its best performance. Therefore, read the article above to find out how many CFM an impact wrench needs and then get an air compressor that fulfils the needs of your impact wrench.


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