How Do You Calculate the CFM of an Air Compressor?

By Staff WriterLast Updated Apr 12, 2020 8:09:13 AM ET

To calculate the CFM (Cubic Feet per Meter) of an air compressor is the same as calculating the output of the compressor. Calculating CFM begins with looking at the specifications of the compressor to find the volume of the tank. The next step is checking technical specifications of the sheet to find out the pounds per square inch (PSI). Calculating the PSI is followed by getting the compressor’s CFM.


The first step after getting the cubic feet volume of the air compressor is to convert its value from gallons to cubic feet by dividing it by 7.48. The second step is calculating the PSI and converting its value to ATM (Atmospheres). This conversion is done by dividing the technical specification value of the air compressor by 14.7. After obtaining the cycle minute value of the air compressor, the figure is divided by 60 to convert it from seconds to minutes. The conversion of the cycle units is followed by calculation of the true CFM. To get the true CFM one multiplies the three figures: the cubic feet volume of the air compressor by the atmospheres of the air compressor by the cycle minute value of the compressor. One must perform these calculations on all air compressors to find the actual CFM air rate of all units. From these calculations, it is possible to differentiate the sizes of air compressors before buying one.