The 8 Best Impact Wrenches of 2021

What to Look for in an Impact Wrench

Power Source

There are three basic types of impact wrenches: those powered by air, AC current, or batteries. 

Pneumatic, or air-powered impact wrenches, are standard in auto-repair shops, but aren’t so popular for at-home or DIY use. These tools are very powerful, lightweight, and generally less expensive than electric impact wrenches, but require an air compressor to work and are generally more tool than required outside of a professional auto shop. 

Corded impact wrenches are next in line when it comes to power, but tether you to the closest electrical outlet. Still, if you need a lot of power and don’t want to be bothered keeping track of a battery’s charge level, this could be the right choice for you. 

Cordless impact wrenches are the most popular type for homeowners, DIYers, and those who do car repair as a hobby. On the plus side, these tools give you the utmost in freedom to use them wherever needed. On the downside, you’ll need to keep track of the battery life, cordless tools tend to be heavier than the other two styles, and they are a little less powerful when it comes to torque.

Torque

An impact driver is all about torque; that’s the tool’s twisting force. Some manufacturers state the torque in foot-pounds of force, while others use inch-pounds. Don’t automatically assume that you need the highest amount of torque; too much torque and you’ll find your fasteners snap in half.

As a general rule, you’ll find impact drivers with torque as low as 100 foot-pounds (1,200 inch-pounds) and as high as 1,000 foot-pounds, as well as everything in between. But for most people not working in professional auto shops, a tool towards the lower end of that range is more than sufficient, while a tool in the mid-range is suited for most automotive work.

Speed

The rate at which an impact driver spins is measured in revolutions per minute. As a rough guideline, most cordless impact wrenches have maximum speeds of anywhere between 1,000 and 3,000 rpm, with the middle of that range being average. Some impact drivers have variable speed controls so you can choose from two or three different settings depending on your needs.

Impact

The “impact” in an impact wrench is a burst of additional power that adds to the tool’s turning strength, and is measured in impacts per minute. As a general rule, most cordless impact wrenches deliver anywhere from 2,000 to 3,000 ipm.

FAQs

What is an impact wrench used for?

If you’ve ever watched the pit crew at a professional car racing event rush out and change the race car’s tires within just a few seconds, you’ve seen an impact wrench at work. These powerful tools are used to turn nuts and similar fasteners with far more force and speed than could be delivered by hand or with a traditional wrench. But the uses of an impact wrench go beyond the racetrack. 

Mainstays in automotive shops, impact wrenches are widely used by both professionals and hobbyists to affix or remove lug nuts from car wheels. But they are also a very useful tool for tightening or loosening nuts, bolts, and other threaded fasteners on all manner of large machinery, during construction or remodeling, and similar scenarios that involve lots of large threaded fasteners. 

While most DIYers won’t need an impact wrench, if you plan on taking on a large home remodel or addition, you enjoy doing your own auto maintenance, or you live on a farm or work on large machinery, an impact wrench is a worthwhile addition to your tool collection.

Do impact wrenches need special sockets?

You might wonder if you can save money by using the same socket set with both your ratchet and your impact wrench. Unfortunately, while it’s generally okay to use an impact-wrench socket with a ratchet, the opposite is not true; affix a regular socket to an impact wrench, and you risk a potentially dangerous shattering of the socket. 

The steel of an impact-wrench socket is slightly softer than the steel used for regular sockets. This allows the impact-wrench socket to have a tiny bit of “give” under the tremendous torque forces of the tool. The harder and more brittle steel of a regular socket is prone to cracking or shattering when exposed to so much force, but entirely suited to the force of your handheld ratchet.

What size air compressor do I need with an impact wrench?

If you have a pneumatic, or air-powered impact wrench, you’ll need an air compressor to use it. Pneumatic impact wrenches are especially popular for work on automobiles, as they have a lot of power, are light in weight, and typically cost less than battery-powered or electric impact wrenches. 

The size air compressor you’ll need depends somewhat on the size of impact wrench you are using. These tools are often named by the size of their drive—the part of the impact wrench that holds the socket. The most common size for the average DIYer or automotive enthusiast is the ½-inch impact wrench, which has enough power to turn the lug nuts of a typical car. 

As a rough guideline, to power your ½-inch impact wrench, you’ll need an air compressor with a 6-gallon tank and an airflow of 3.5 to 5 cubic-feet-per-minute (cfm) at 90 pounds-per-square-inch (psi).

For a smaller impact wrench with a ¼-inch drive, an air compressor with 1 to 2 cfm airflow at 90 psi is sufficient, while a tool with a ⅜-inch drive does best with an air compressor that has 3 to 3.5 cfm airflow at 90 psi.

Why Trust The Spruce?

This article was written by Michelle Ullman, the tool expert for The Spruce. She has extensive experience not only in writing about all things related to the home, but also in carrying out various DIY projects, including landscaping, painting, flooring, wallpapering, furniture makeovers, and simple repairs.