Air Compressor CFM Calculator + FAQs

| Last Updated: March 28, 2021

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In the article below, we'll discuss air compressor CFM by answering various important questions on calculating CFM correctly and how to apply that to your air compressor. 

Compressed Air CFM Calculator 

When you're browsing on the internet, they don't always tell you the air compressor's CFM. Therefore we've included a CFM calculator to help you with that. 

How To Calculate CFM

Calculating your CFM isn't as easy as putting some numbers into a calculator; a few tasks are included with the calculation. 

How To Calculate CFM Of Air Compressor

The easiest way to explain this calculation would be explaining it step by step. It can get complicated with all the dividing and multiplying; it might take a few re-reads. 

  1. Divide the total number of gallons by 7.48. This will give you the volume of your air compressor in cubic feet. 
  1. You then multiply the cycle period, which is when the air compressor turns on during use and turns off during use. You will also need to record the pressure rating at these two moments. 
  1. Subtract the PSI when the compressor turns off with the PSI of when it's switched on. This gives you the PSI usage difference. 
  1. Once you have the difference, you then want to divide it by 14.7; this will give you an ATM measurement. 
  1. Multiply the total volume of the air compressor in cubic feet with the ATM unit. 
  1. You then divide 60 with the total number of seconds in one air compressor cycle. 
  1. Once you have that number, you multiply that number with whatever number you got in step five; the end calculation will provide you with your air compressor's CFM. 

Hold up, are you interested in other topics related to air compressors? If so, these might be something to check out: 

What Does CFM Mean? What Does CFM Stand For?

If you've ever read a buying guide for air compressors, you'll notice that in every single article, it mentions CFM as an essential feature. Below, we'll explain why it's so important when operating pneumatic tools. 

What Does CFM Mean For Air Compressors?

CFM stands for cubic feet per minute. CFM is a measurement of airflow; it's the rate at which pressurized air travels within a minute. 

The reason this is important is that air tools all have various CFM requirements. The CFM of your air compressor must meet your air tools' minimum rate for it to work effectively.  

How Many CFM Do I Need? - Air Tool CFM Chart

Standard construction tools like drills or nailers require less than 5 CFM in most cases. However, other tools like orbital sanders, 1-inch impact wrench, sandblasters, and spray painting guns can require 20 CFM upwards. 

CFM requirements can also change depending on what nozzles you're using; the wider the nozzle on a tool like a spray gun means you'll require more CFM. 

Air Compressor CFM Chart

Informational Overview 

When looking at various air compressors' capabilities, you'll notice they sometimes mention both CFM and SCFM; there are some differences between the two measurements, which we discuss below.  


SCFM and CFM are common ways to measure airflow to an air tool within a certain period. CFM is when temperature, humidity, and pressure are all unknown variables. 

However, SCFM is measured under environments where temperature, pressure, and humidity are considered and known. 

What Does SCFM Stand For? What Does SCFM Mean?

SCFM stands for standard cubic feet per minute. This reason for this name is that manufacturers will measure the cubic feet per minute. 

Still, they'll be doing it in a controlled, standardized condition, including factors such as atmospheric pressure, ambient air pressure, humidity, and temperature. 

What is SCFM on Air Compressor?

SCFM ratings tend to be higher than a CFM because manufacturers measure the CFM of an air compressor at a standard of 90 PSI or lower. 

Whereas with the SCFM, manufacturers will increase the airflow to include room for variables.  


PSI stands for pounds per square inch. This measurement is to show how many pounds per square inch your compressor can provide.

If you use a compressor that provides 30 PSI, but the tool requires 120 PSI, it won't give enough pressure to operate the device. 

CFM and PSI work together as CFM will ensure a sufficient airflow, while the PSI ensures it can provide the correct level of pressurized air to operate the tool. 

Conversion PSI to CFM 

There's no physical way to convert PSI into CFM. They're both related, but there isn't any method of converting these two. 

However, if you lack PSI, you could always invest in a larger tank connected to your air compressor via another hose. A low CFM can sometimes be worked around by changing to a narrower nozzle. 


CFM and SCFM can be confusing, thankfully most manufacturers tell you both the CFM and SCFM before buying, but if you ever forget, you now know how to calculate it.

People Also Ask

Below we've compiled and answered some of the most common questions regarding CFM when using air compressors. 

How Many CFM Per Ton 

CFM per ton is more related to HVAC; it's 150 CFM per ton usually. However, if you're asking about air compressors' cooling abilities, this is done by built-in systems or lubricating oil. 

How To Increase CFM On Air Compressor 

There are two standard methods. The first is merely joining two compressors together. The second is by lowering the regulator; this keeps the compressor running for longer, lower pressure will build in the tank, increasing the CFM. 

What Is Air Compressor CFM Rating?

CFM is a measurement of airflow over some time. It stands for cubic feet per minute. The rating itself indicates to the user if they can use the compressor with specific tools. The CFM of the compressor must match or be higher than the pneumatic tool.