What Size Air Compressor Do I Need?

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what size air compressor do you need

Air compressors come in many shapes and sizes, and choosing the right one for your needs can be a challenge. Horsepower, PSI (Pounds per Square Inch), gallon size, and CFM (Cubic Feet per Minute) can all play a role in getting the most from your machine, but the most important factor is how you’ll be using your compressor the most. If you use larger air-powered tools, you may need a bigger tank size to keep up with the air demands. If you’re using smaller tools or filling tires at home, a smaller tank may be fine. We’ve broken down some of the more common uses for air compressors below to help you determine what size and specs are best for you.

What is CFM?

Gallon size and CFM are important factors in choosing an air compressor. CFM, or cubic feet per minute, is the volume of air moving through your compressor as you use it. If the CFM is too high, your compressor’s air will drain too fast and you’ll have to stop working while it refills. If it’s too low, you won’t have enough power for your tools. To determine what CFM you’ll need, look at your tool’s CFM requirements, then multiply by 1.5 to determine what capacity you need from your air compressor.

What Size Do You Need for Tires?

For home use, a simple 3- to 6-gallon tank is fine, and a CFM of 2-3 is perfect for the continuous air dispersal needed to fill a tire. The small tank size is also ideal for portability. An air compressor of this size is great for general home use and smaller-sized air tools. Check out Best Pancake Air Compressors 2019 for the perfect buyer’s guide.

pancake air compressor

What Size Do You Need for Air Tools?

For the best performance, a gallon size of 8-10 is perfect for most air tools. Aim for 3-5 CFM, as well. While these are generalized sizes to give you the best versatility, different tools can require different specs. We’ve given you an ideal air compressor size for each of the three common air tools below.

Impact Wrench

You’ll be gulping a lot of air if you’re using an impact wrench, so you’ll want a decent tank size and a stronger CFM. Aim for around 6 gallons and 5 CFM for best performance. Check our Best Air Compressors for Impact Wrenches page for our top picks to help you decide what to purchase.

Air Compressors for Impact Wrenche

Nail Gun

This is another air gulper. You’ll likely be nailing in rapid succession, so you’ll need a good tank. Aim for 5-6 gallons and around 5 CFM. Check out our Best Air Compressors for Nail Guns page for the best nail gun options available in 2019.

Air Compressors For Nail Gun

Air Ratchet Tool

You can get away with a little less here. Aim for 3-4 CFM and 5-6 gallons for the best performance. Check the CFM specs on your air ratchet to make sure you’ve got the right CFM to get the best performance from your tool.

Air Ratchet Tool

What Size Do You Need for Painting?

Look at larger tank sizes for professional painting jobs. If you’re planning on spraying the inside or outside of a house, stain a fence, or paint a car, you’ll be using almost constant air. Of course, painting a house is a much bigger job than painting a car, so the size you need will differ.

Home Painting

For best results, use a compressor with a capacity of 5-6 CFM. Because you’ll be spraying nearly constantly, a larger, 10-gallon tank will keep you from waiting for the compressor to refill every few minutes.

Painting a Car

You’ll still need plenty of air capacity for car painting. Because of the smaller surface area, you can get away with a 6- to 8-gallon tank, though a larger tank will ensure you won’t have to pause while the tank fills. Aim for 5-6 CFM for best performance.

spray painting on car

Image credit: BarbieJ, Wikimedia

A Few Final Words

We’ve focused primarily on CFM and tank size for this article, because air compressors are typically already built with the right ratios of horsepower and PSI for good performance. You shouldn’t have to worry about factoring these in unless you have more specialized needs.

As with any power tool or machine, it’s a good idea to wear ear protection while using an air compressor. Some models reach high decibel ranges that can damage your hearing. Before purchasing an air compressor, also consider how portable you need it to be. A larger tank will always come with some added heft in pounds. Good luck finding the best air compressor. We hope this guide has helped you make that decision.

Related: How much should you actually pay for an air compressor?


Header image credit: Paul Sableman, Flickr

About the Author Ryan Doskocil

Ryan is a freelance writer from Arizona. When he's not blogging about his favorite hobbies, he's writing fiction, hiking or running in the great outdoors, and spending time with family.