To calculate the approximate CFM of your air compressor, enter your receiver tank volume, start and end pressures, and the time required to reach the end pressure. This form requires that Javascript is enabled in your browser.

Volume (gal):
Start Pressure (PSI):		End Pressure (PSI):
Minutes:		Seconds:
CFM:

While attempting to rework the custom pluming on an old Harbor Freight compressor, I was having a difficult time figuring out what connectors I needed to order. This guide is, by far, the best explanation of the many types of fluid fittings that are out there:

https://www.hydraulicsdirect.com/Fitting-Thread-Chart-s/1934.htm