The first step - determine how much volume flow your tools need. Measure it in LPM (litres per minute) or CFM (Cubic feet per minute).
Second step - Add 50% to the required flow to be on the safe side for stable airflow. For example - a typical spray gun requires 10 CFM, 10 +50% equals to 15 CFM, so suitable air compressor should produce 15 CFM.
Always observe if you need single or three-phase connection.
Please note that oil-free compressors are mandatory for the dental and food industries.
Please keep in mind that recommendation above this text applies only for one tool/unit connected per compressor.⚠️