What Size Air Compressor Do I Need for Air Tools?

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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
Drill470-90
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
Staple Gun270-90
Tire Inflator2125-150

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Comments

  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.

    Reply
    • 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.

      Reply
      • 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?

        Reply
        • 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).

          Reply
          • Peter Palmer may have been asking about using an air tool to release and re-tighten the wheel nuts, rather than only to inflate the tires. If this is the case, what size compressor is recommended?

          • Good point. CFM at 90psi is going to be the most important factor. For a typical 1/2″ impact wrench, you’ll need around 4.0 CFM (but the tool itself will have the exact requirement). The size of the compressor is less important since continuous airflow is not needed (ie: loosening 5 lugs, swap wheel, retighten). But for the CFM requirements, you’re usually looking at a 10 gallon tank minimum anyways.

  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?
    Thanks,
    Guy

    Reply
    • 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.

      Reply
  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?

    Reply
    • 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.

      Reply
    • We have a 60by50 heavy duty truck shop we have a large compressor we plan on running a 1/14 with 3/4 drops to reels ect do u think this will be sufficient ty pat

      Reply
    • Honestly if you just want an impact tool check out a 18v model from dewalt/Milwaukee you can get a kit under $200 and it has not air hose. I love my midrange impact from dewalt (dcf894). Check ebay for good deals, people break up their kits and sell them off cheap

      Reply
  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.

    Reply
    • 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.

      Reply
  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?

    Reply
    • buy the biggest you can afford. i have a blast cabinet that will run for 1 minute with a 30 gallon ingersoll rand compressor. id look for 60 gallon with 15cfm or better, get 5hp not the smaller 3.7hp ones . i just bought a quincy qt54 to keep up with my cabinet.

      Reply
  6. I’m thoroughly confused on the whole ratings system. I have a 30 gallon husky compressor that says its rated at 5.1 scfm@90psi and I just bought a small 20lb sandblaster from harbor freight that says it’s rated at 6 cfm@60psi. What psi do I need to set on the regulator to get the best results?

    Reply
  7. I purchased an AC flush canister. I use it to flush my clients vehicle AC system on demand so I am always on the road. What portable 12volts DC air compressor can I purchase which has enough cfm at 0 psi to push solvent through the flush canister into the Cars coil evaporator and out. I am tired of carrying a cumbersome ac compressor. Please advice.

    Reply
  8. 60 psi, but your compressor won’t be able to achieve 6 cfm regardless of pressure. There is this part that is always left out, sometimes the cfm rating is for 15 sec of use in 60secs. If so to get the full throttle, you multiple by 4. So check if your sandblaster is rated at 6 cfm full load, and get a compressor that runs that level of cfm continuously.

    Reply
  9. I have a half inch snap-on impact gun my job had a 80 gallon air compressor I am trying to find a compressor for my house will 60 gallon air compressor a Kobalt be more than sufficient enough to run that impact gun it does not have a dual compressor head is a single compressor head

    Reply
    • You’ll want to check the CFM requirement of the impact gun. It should be around 4 CFM at 90PSI. Almost any 60 gallon compressor would be fine but even a 20 gallon should have more than enough stored air capacity to keep up with use of the impact wrench without having to pause what you’re doing to allow pressure to recover.

      Reply
  10. I need a compressor to inflate my used motor home tires to 90 lbs. What size compressor would you recommend? I’m not using other air tools. I inherited my dad’s ancient 6 gallon compressor that says it does 100 psi but it will only get the tires to 74 lbs.

    Reply
  11. Hi CHRIS
    I’m currently learning to upholster and need advice for the right compressor to run a staple gun that’s going to give good operating performance.
    Please advise

    Reply
    • Check the minimum requirements for your specific staple gun but they generally have fairly low requirements (maintain 70-90 PSI) that almost any compressor will do. For best results, you’ll want a CFM of at least 2.0 but slightly less should usually be ok. Tank size isn’t a huge deal since you’re not using continuous air but I’d personally go with 2+ gallons. Here are a couple good options. I love Rolairs since they are super quiet. The DeWalt is an excellent all-around compressor.

      Reply
  12. I’ve got the makita mac5200 the tank pressure stops at 60 and the reg. Stops at 40 then they will not go any higher . Has oil . No leak that I can hear or feel and I have it turned all the way up . Once it hits 60-40 it’s starts making a sounds that is easily letting you know to turn me off or I’m done !!!!

    Reply
  13. Hello,
    I am planning to use a Chicago Pneumatic Air Scribe (CP9361) continuously for hours with a portable compressor. It is possible that in the future I may hook up another air scribe to the system as well. The manual states that 90 PSI is needed, but says nothing about the CFM requirement or tank size needed. What would be the best portable air compressor for this tool?

    Reply
    • The CP site lists 0.28 CFM as the average consumption but other sites that sell it show a 1.1 CFM at full load which is more important. However, since air scribes use A LOT of air, the larger the tank size and the higher the CFM, the more likely is the compressor will be able to keep up and cycle less often.

      I’d recommend at minimum, a 6-8 gallon tank with a 2.0+ CFM. It’s still going to be cycling on every 1-2 minutes though. A larger tank will be more important than CFM but if you want good portability, I’m a big fan of California Air Tool’s 10-gallon model.

      Something larger like this Husky 30-gallon would be better though and would better handle 2 scribes. Going up in quality, Industrial Air would be a bit better.

      Reply

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