How to Size an Air Compressor? Explained in detail

Are you want to buy an air compressor and don’t understand which one is better for you? In the market, many sizes of air compressors are available. It is difficult to choose the right compressor for your job. But it becomes easy if you can find out the right size of air compressor according to your job. In this article, we will discuss how to size an air compressor

Before buying a compressor must consider its size. A proficiency compressor is determined by its CFM and PSI. You have to understand all the factors for sizing the air compressor. We will give a clear concept of all the factors sizing an air compressor. 

Starting from painting cars to filling up car/bike tires, pneumatic tools like framing nailers, roofing nailers, and impact wrench, knowing the proper air compressor size is important.

What is an Air Compressor?

An air compressor is one kind of converter device. This device uses an electric motor, diesel, gasoline engine, etc for converts power into potential energy and stored it in form of pressurized air. 

An air compressor uses for different purposes like supplying clean air to a submerged diver, filling cylinders of clean air, inflating tires, etc. This device is available in any size. Different size of air compressor is needed for different work. Here, we will show you the air compressor sizing calculator.

Check >> CFM Calculator for Compressed Air

How to Size an Air Compressor?

An air compressor comes in different sizes. It is difficult to measure the perfect size according to your work. Sometimes it can be the small sometimes big size. Here are some considerations for look different sizes of air compressors. We can show the air compressor sizing calculator in excel with the flowing considerations. 

  • Airflow
  • Pressure requires
  • Power source
  • Duty Cycle
  • Air tank volume
  • Physical dimensions

Knowing about the airflow

Airflow is an important criterion for pneumatic tools. Airflow means, how much the compressor delivers compressed air for the job at a particular time. The volume of air is rating with CFM. you have to measure the CFM to know the airflow of your air tools. 

Airflow is not the same for all the air tools. It depends on the air tools. For example, one to two CFM need a small air tool, 90 CFM needs a pavement breaker, and some heavy-duty air tools need more CFM. You have to know about the CFM to understand how much airflow you need. 

What is CFM?

The full meaning of CFM is cubic feet per minute. It is a unit of the volume of air. That means how much the volume of air is compressed in a minute. You can know the airflow power of a compressor with CFM. 

The air that enters the compressor depends on heat, conditions, and humidity. So, CFM is hugely influenced by the atmosphere. The compressor will be perfect for your job if you know the CFM.

How to measure CFM for air tools?

Finding out the CFM of an air compressor is a mathematical term. You have to know this,

CFM = Cubic Feet per Minute


  • Cubic Feet is a unit of volume, and 
  • Minutes is a unit of time
  • 1 cubic foot is =  28.317 Liters. 
  • Therefore, 1 CFM = 28.31 LPM or Liters Per Minute
  • Similarly, Liters per Second (L/sec) or Cubic meters per hour are units of the flow of air.

The amount of CFM depends on how many tools you have to use at a time. If your compressor power one tool at a time then you have to calculate in this way. 

  • First, find the CFM requirements of all the tools that you will use, 
  • Then, choose the highest CFM, 
  • Now, multiply the highest CFM by a safety factor of 1.5

If your compressor power multiple tools at a time then you have to calculate in this way.

  • First, add up the CFM of all the tools that you plan to use
  • and multiply the total by 1.5

You have to remember that light-duty compressors are good for only single tools. Heavy-duty compressors are good to handle multiple tool duties and provide multiple outlets. So, you have to ensure that your compressor can power all the tools that you plan to use.

How much pressure require for your air compressor?

The measurement unit of air pressure in PSI. The full form of PSI pounds per square inch. This unit is also written as PSIG. The meaning of PSIG is pounds per square inch gauge. We can know the relation to the atmospheric pressure by PSI. which means if the PSI level is high the air level is high that air is stored in the compressor tank.  

The right size of compressor mostly depends on PSI. So it is important to determine the right PSI. Before determining PSI, check the tool that you want to use. Because the correct PSI depends on the type of the tool. The air compressor requires 90 to 100 PSI for light work like metal or woodworking and for industrial work or heavy-duty you need more than 100 PSI. 

The market has so many air tools and they require different PSI. For example, grease guns and tire inflators need about 120-150psi. 

How Much Power Source do You Need?

The power of an air compressor is measured by horsepower or HP. This unit is used to complete the task of the compressor. Normally, an air compressor rating is 1.5 and 6.5 HP, and 15 HP is used in large work stationery.  

Duty Cycle:

The duty cycle means how long the tank of a compressor needs to fill with air. One full cycle is the total time to fill up the tank. 

If an air compressor’s total cycle time is 10 minutes and it ran for 7 minutes during that time. That means the duty cycle of the compressor is 70%. 

To find out the duty cycle, you need this mathematical formula.

Duty cycle percentage = compressor time on/cycle time

Air Tank Volume

A tank is a store of compressed air that is also called a receiver. Determining the air tank size is important. Normally compressor comes with many tank sizes. You can find a 1 to 60-gallon tank in the market. Also, you can find more than 60 gallons of tanks. All the tanks aren’t used for the same job. In the industry used more than 60-gallon tanks and other sizes of tanks are also used in different jobs.

To know the size of the compressor, you have to determine the tank size. We can know how long the air tools will run before turning the motor on once again with the tank size.

You can calculate the tank size with this formula. 

Air receiver tank size calculation:

V= 14.7*Qr*t / (P1-P2)


V = volume of the receiver (ft3)

Qr = consumption rate from the receiver (CFM)

t = time (in minutes) that the receiver can supply sir between maximum

P1 = maximum operation pressure 

P2 = minimum allowable pressure

Physical Dimensions

Before buying an air compressor, you have to know how much space you have. You have to choose a place where the air compressor can perform very well. Normally, an air compressor comes with large storage and the tank takes more space per square inch.

We recommend keeping a minimum three-foot radius around the compressor. For doing this, your compressor provides proper airflow and other services. You can determine the physical dimensions with feet, meters, footprints, and volume. 

CFM charts for Air Tools

Most air compressor requires 10 to 110 CFM and 70 to 90 PSI. But CFM and PSI is depends on the tools that you plan to use and the type of work. For example, an air tool of 10-15 CFM is enough for tire inflation, and home tools such as air grinders, sanders, nail guns, and, air hammers among others. On the other hand, an air compressor with 70 PSI can handle light to medium work. Here is a chart of PSI AND CFM according to the air tools. It helps you to choose the right air tools for a particular job. 

AirToolsAverage CFM @ 90 PSIAverage Operating PSI 
Angle Grinder5-890-100
Air Hummer490-100
Brand Nailer0.570-90
Farming Nailer2100-130
Die Grinder570-90
Disc Sander2090-100
Grease Gun3120-150
Paint Spray Gun4-890-100
Tire Inflator2125-150


  • Choose a compressor with slightly higher CFM on your requirement powerful tools.  
  • If your compressor gives power multiple tools, add up all the CFM to determine the right compressor.  
  • Don’t give more importance horsepower than other factors. Determine all the factors.
  • Don’t think that more horsepower means a good compressor.
  • Some compressors are rated peak horsepower some are rated at the tunning horsepower of the motor. 


How do I know what size air compressor I need?

You have to find out the highest value of PSI and CFM of your air tool. Then you can know the correct size of air compressor that you need. 

How big of an air compressor do I need to run a 1-inch impact?

The size of the air compressor is determined by some considerations and CFM and PSI are the most important factors. For a 1-inch drive, 1′′ drive impact wrench requires 10 CFM at 90 PSI.

What is a good size air compressor to run air tools?

A good size air compressor is 10 to 112 CFM to run air tools. This power is enough for housework. 

Final Thought

Air compressor comes in different sizes and all the compressor needs n different job. You have to find out the correct compressor according to your work. The right sizes of the compressor depends on various factors. However, a proficiency compressor is determined by its CFM and PSI. We already gave a clear concept about how to size an air compressor. 

You should pay more attention to CFM and PSI. Also, check the space where you set the compressor. Because compressor needs more space for provides best service. 

What size of air compressor do I need for Impact Wrench
What Size Air Compressor for Framing Nailer