What Size Air Compressor Do I Need for Air Tools?

Whether you’re a DIY mechanic, a weekend warrior, or just an everyday garage tinkerer, having a good set of tools is an important step in making your projects run smoothly.

One of the first things you’ll want to decide is whether to stock up on electric tools or invest in quality air tools (or both). Some of the advantages of air tools include:

  • Longer lifespan than comparable electric tools
  • More power (in many cases)
  • Less weight to reduce operator fatigue
  • Reduced heat output
  • Little to no risk of fire hazard or electric shock

To get started with air tools such as impact wrenches, nail guns, and paint sprayers, you’ll need a good air compressor to run everything. Since this compressor will be your power source for all these tools, you’ll want to make sure you have the right type and size.

What Size Air Compressor Do I Need?

Before buying an air compressor, it’s important to figure out what your exact needs are so you can find the perfect fit. Start by asking yourself a few basic questions:

What types of projects am I going to be doing?

Occasional maintenance tasks or bigger construction projects? Automotive repair or home upgrades? Someone putting up a shed in their backyard will obviously need something more powerful than a hobbyist airbrushing some figurines.

What types of air tools will I be using?

Some tools, particularly those that require constant air such as a sandblaster, will need an air compressor with a bigger tank and more airflow. To operate something like a brad nailer, almost any small compressor will do.

What kind of power source do you have available?

Most air compressors can plug into a standard home outlet, but some larger compressors require a 240 volt source. A few others are powered by gasoline for when an electrical outlet simply isn’t available.

How much space do I have?

Air compressors with large tanks can take up a lot of room, so if you have a smaller space to work with, you’ll want to be sure to find a compressor that will fit in the space you have. A 6-gallon pancake compressor will fit in almost any garage but a 30-gallon stationary unit may not.

Where will I be using it?

If most of your projects will be done in one place (like a garage or workshop), you won’t need to worry much about the design of your air compressor. However, if you plan to move your tools around frequently, you’ll want to look for an air compressor that is lightweight and easy to carry, or has wheels for better portability.

Once you have this information in mind, you’ll have a good idea of what size of air compressor is best for you.

Tank Size

Air compressor tank sizes run anywhere from less than 1 gallon all the way to 60 gallons (or even more). The tank size simply determines how long air tools can run before the the motor in the compressor has to turn back on to create more compressed air.

Because certain air tools (grinders, sanders, etc.) require a continuous flow of compressed air, they’ll need a larger tank than tools that operate in short bursts, such as brad and framing nailers. The less amount of times the motor has to cycle on and off, the better it is for its lifespan.

If you were to trying to set up a large inflatable swimming pool with a 1-gallon compressor, the motor would be constantly running. Combined with its low airflow (see CFM Requirements below), you’d be lucky to be done in a couple hours. Now try the same thing with a 30-gallon compressor, and you’d be done in a few minutes.

If going with a large stationary air compressor in your garage, you’ll definitely want to invest in mounting a quality air hose reel in a central location for ease of use and organization.

Air Tool CFM Requirements

The amount of airflow an air compressor produces is the most important rating you’ll want to pay attention to when shopping for a compressor. Noted as “Standard Cubic Feet per Minute (SCFM or CFM), this number will need to at least meet the minimum CFM rating of the air tool you’ll want to use.

Since CFM changes depending on what you set the pressure (PSI) at on the compressor, us the “CFM at 90 PSI” rating of air compressors when comparing units.

Horsepower is another common rated touted by air compressor manufacturers. It’s not as important as the CFM rating but can give you a general idea of a compressor’s power. Think of it this way:

  • HP determines how powerful the air compressor’s motor is (to refill the tank).
  • CFM determines how much power the air compressor provides to air tools.

Every air tool has a recommended CFM requirement that’s set by the manufacturer. To determine what CFM rating you’ll need in an air compressor, take the highest CFM rating of your current air tools (or tools you plan on purchasing) and multiple that by 1.5.

This will give you some wiggle room since CFM can vary a bit during operation, you may want to connect a couple air hoses to run multiple air tools at the same time (if your model allows it), or plan on upgrading air tools in the future.

Air Tool CFM Chart

Here are some of the most common air tools and their average CFM requirements. Keep in mind that air tools are rated on a 25% duty cycle (in use for 15 seconds out of every 60 seconds) so for continuous use tools such as grinders, you may want to multiple the CFM number by 4.

Air ToolAvg. CFM @ 90 PSIAvg. Operating PSI
Air Hammer490-100
Angle Grinder5-890-100
Blow Gun2-390-100
Brad Nailer0.570-90
Die Grinder570-90
Disc Sander2090-100
Framing Nailer2100-130
Grease Gun3120-150
Hydraulic Riveter490-100
Impact Driver (1/2")490-100
Impact Driver (3/4")790-100
Impact Driver (1")1290-100
Impact Wrench (3/8")390-100
Impact Wrench (1/2")490-100
Impact Wrench (1")1090-100
Orbital Sander6-970-100
Paint Spray Gun4-890-100
Ratchet (1/4")390-100
Ratchet (3/8")490-100
Speed Saw490-100
Tire Inflator2125-150

Related Posts:


  1. Quote “If you were to trying to set up a large inflatable swimming pool with a 1-gallon compressor, the motor would be constantly running. Combined with its low airflow (see CFM Requirements below), you’d be lucky to be done in a couple hours. Now try the same thing with a 30-gallon compressor, and you’d be done in a few minutes.”

    Because this was listed under Tank Size, it is backwards. The 30 gallon compressor will not inflate the pool faster because it has a larger tank, rather that it has a larger compressor on that tank.

    If the compressors were instead equal and the difference was only the tank size attached to each, then the one with the larger tank would take longer to full the swimming pool because it compresses at the same rate yet has the volume of the tank to fill in addition to the pool. Granted at low inflation pressures the difference won’t be much and a modest sized compressor isn’t even the right tool for something like these, rather you would be better off with a leaf blower, maybe even the blower output of a shop vac.

    • Correct, it’s technically not due to the tank size and instead how powerful the motor is. But generally speaking, a 30 gallon model is going to have a much more powerful motor than a 1 gallon model and thus capable of more sustained airflow.

      • I would like to be able to rotate my tires. What size compressor do I need? Also, I have a 20 gallon compressor but will only fill up to 30 psi on dial. What can I do to fix this?

        • Pretty much any compressor (even 1-gallon or small 12v) will be able to inflate tires. Sounds like your 20-gallon has a leak somewhere if it can’t get above 30 psi (or the dial is faulty).

  2. Hello,
    I recently purchased a small plasma cutter and believe it needs a consistent air feed rate of 60 PSI. Can you please help me figure out what size compressor I’ll need to buy?

    • Any compressor you buy will be able to easily deliver 60 PSI. What you want to look for is the CFM requirement (usually measured at 90 PSI). The plasma cutter should say something like “requires 4.0 CFM @ 90 PSI” so you’ll want a compressor with at least that.

      As for tank size, if you’re just making short cuts, you can probably get away with a smaller 6-8 gallon tank but for longer cuts, look for something in the 15-20 gallon range.

  3. What size compressor would I need for Mechanical work. For instance, The main bolt on the pulley on my crankshaft is installed at 250 lbs/ft. What SCFM and PSI do I need? How do I translate that? Do I need a bigger gun?

    • The impact gun you’re using is going to have a CFM requirement. It’s usually in the 3-5 SCFM range. Look for an air compressor that has a CFM rating of at least that number measured at 90 PSI. Most any impact wrench will handle 250 lbs-ft of torque.

  4. I wanted to know what size tank is ideal for an air ratchet? I had an 8 gallon tank and I thought it would do the trick. My impact wrench worked fine with it but I could get no use out of the ratchet. Im buying another one and want to make sure I purchase the right compressor this time. Thank you.

    • A ratchet and impact wrench work similarly. The impact wrench actually requires more airflow most of the time. The fact that your impact wrench works yet the ratchet doesn’t might mean the ratchet has higher requirements. Check the air ratchet manual or on the tool itself to see what the minimum CFM is to make sure your compressor can handle that.

      8 gallon “should” be a big enough tank size for an air ratchet so I’d start with comparing the tool’s required CFM vs the compressor’s CFM output at 90psi. A larger tank size will just allow you to run the tool longer without the compressor having to get back up to pressure.

  5. I plan on using an air compressor for sand blasting a d spray paint the recommendation of 6 cfm @ 40 psi. What do I need to shop for in air compressor type?

Leave a Comment