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How Do I Size a Piston Compressor for my workshop?

Learn how to properly size your piston compressor based on your needs

Air compressors should be sized based on the volume of air (cfm/m3h) and air pressure (psi/bar) needed to do the job and not horse power. Single stage air compressors have a maximum pressure of around 130 psi (9 bar) while two stage air compressors have a maxinum air pressure of 175 psi (12 bar). Tank size is typically not a critical factor in sizing a compressor.

Calculating your need

  1. What is the maximum pressure you need? (refer to the table below for a general guideline)
  2. What is the electrical requirements (voltage/phase)?
  3. How many people will be using air at any time (maximum)?
  4. Is this a body shop or mechanical shop?
    1. Body Shop: 12-15 cfm/person X # of people
    2. Mechanical Shop: 3-5 cfm/person X # of people
  5. Now add at least 25% to your total cfm required in order to allow for duty cycle.


Typical cfm consumption by tool

Tool/Equipment Air Pressure (psi) Air Pressure (bar) Air Consumed (cfm) Air Consumed (l/s)
Impact Wrench 3/8-1/2 70-90 4.8-6.2 5 2.36
Impact Wrench 1/2-3/4 70-90 4.8-6.2 10 4.72
Impact Wrench 3/4-1 3/4 70-90 4.8-6.2 20 9.44
Air Ratchet 70-90 4.8-6.2 3-5 1.42-2.36
Body Sander (Oribital) 70-90 4.8-6.2 12 5.66
Tire Changer 125-150 8.6-10.3 2 0.94
Bead Breaker 125-150 8.6-10.3 12 5.66
Blow Gun 70-90 4.8-6.2 3 1.42
Die Grinder 70-90 4.8-6.2 7 3.3
Screwdriver #2-6 Screw 70-90 4.8-6.2 5 2.36
Screwdriver #6-5/16 Screw 70-90 4.8-6.2 10 4.72
Paint Spray Gun (Touch Up) 70-90 4.8-6.2 4 1.89
Paint Spray Gun (HVLP) 40-60 2.7-4.1 15 7.08
Nailers/Staplers 70-90 4.8-6.2 2-4 0.94-1.89
Chart intended as a reference only. Actual air consumption may vary.


    Tool/Equipment Air Pressure (psi) Air Pressure (bar) Air Consumed (cfm) Air Consumed (l/s)
    8.6-10.3
    Chart intended as a reference only. Actual air consumption may vary.


      Tool/Equipment Air Pressure (psi) Air Pressure (bar) Air Consumed (cfm) Air Consumed (l/s)
      8.6-10.3
      Chart intended as a reference only. Actual air consumption may vary.

      Thank you CP Compressors for this video.


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