Air Compressor CFM Explained: Matching Your Tools to the Tank

Compressor marketing is full of CFM numbers that are not directly comparable. Here is what each one means and which one to use for sizing.

The numbers

• Displacement CFM: theoretical — multiply piston bore × stroke × RPM. Ignore for sizing.
• CFM at 0 PSI: a useless marketing number.
• CFM at 90 PSI: the one to size to — actual delivery at the pressure your air tools need.
• SCFM: standard cubic feet per minute, corrected for temperature/humidity — used for industrial compressors.
• FAD: free air delivery — used by European brands, similar to SCFM.

The sizing rule

Find the highest-CFM tool you will run for more than 60 seconds continuously. Take its CFM @ 90 PSI rating. Add 30% headroom. That number is your minimum CFM @ 90 PSI requirement.

Typical CFM at 90 PSI

• Impact wrench 1/2″: 4.5 CFM
• Impact wrench 1″: 10 CFM
• Die grinder: 5 CFM
• DA sander: 11 CFM
• HVLP paint sprayer: 13 CFM
• Media blaster: 15 CFM

Skip the math

Our [Compressor Output Calculator](https://gas-and-diesel-engine-equipment-guide.com#eeg-compressor) lets you select your tools and use intensity, then recommends a matching CFM, tank, PSI, and stage class.