Informational Guide

How Does An Impact Wrench Work?

We give you the inside scoop on how an impact wrench works in this detailed guide.

When you start on an automotive repair, you want to have the right power tools at hand. Otherwise, you could waste a lot of time and face plenty of frustration. Impact wrenches are used when high torque output is needed, but you need to have the right model by your side, but you must also know to operate it. So, how does an impact wrench work? We give you the inside scoop.

An impact wrench is a power tool that provides high torque output with minimal effort from the user. What do you use an impact wrench for? While commonly confused, the impact wrench is completely different from the impact driver. The impact driver has a hex opening for bits, while the automotive impact wrench holds sockets that fit a wheel lug with ease. In fact, that’s mainly what the impact wrench is used for, changing tires. Yet, it can also be used on engine manifolds and other parts of the car. With that said, there are other product assembly, construction projects and heavy equipment maintenance tasks that might require an impact wrench.

How Does An Impact Wrench Work?

To understand how this power tool works, it helps to first look at what parts are included. We have this -  how does an impact wrench work diagram to help you understand what we are talking about.

The impact wrench contains either an air or electric motor that applies a quick, forceful twisting motion to the nut. This pressure is applied in short bursts, generally lasting less than five seconds. With the continual shots of force, the fastener will begin to move, even if it had been previously stuck. That’s why the impact wrench is used for removing rusted on lug nuts and other difficult parts.

Here is a helpful video if you want to understand - how does an electric impact wrench work?

Types of Impact Wrenches


The corded impact wrench needs a power source in order to operate, but you won’t need an air compressor. Are electric impact wrenches as good as air-powered impact wrenches? While you won’t get as much power out of some electric impact wrenches, these are generally the best option for home mechanics.


The air impact wrench is the most powerful option and is typically used in garages. How does an air impact wrench work? You need an air compressor to operate this wrench as it doesn’t run off of electric power. If you plan to use your impact wrench on the go, this isn’t a viable option.


The only time you would want a hydraulic impact wrench is if you are working on heavy equipment. These offer the best power-to-weight ratio. That’s why the majority of hydraulic impact wrenches are found in industries and machine shops. These are even used in some underwater applications.


air impact wrench operate like an electric model, except it doesn’t need to be plugged in. Instead, it uses a battery pack, similar to a cordless drill. This option is convenient and easy to take on the go, but it’s the best choice if you need long periods of use. Once the battery dies, you won’t be able to use the tool.

Benefits Of Using Impact Wrenches: Who Should Get One?

Impact wrenches are mainly used in the automotive field. It’s a common tool to rely on when removing stubborn lug nuts. Any repair shop is going to have an impact wrench, but are impact wrenches worth investing in as a home user? If you prefer to do some of your own automotive work, we think it's wise to have one in your garage. It can also be handy for heavy equipment assembly, maintenance, construction projects, and manufacturing.

People Also Ask (FAQs)

How powerful of an impact wrench do I need?

Impact wrenches come in a variety of torque options. When choosing the one that will suit you best, base your decision on the application you plan to use it for. Over torquing a nut can cause serious implications, so it’s often best to err on the side of caution.

What is the difference between an impact driver and impact wrench?

The impact driver is needed to drill screws into metal or wood, while the impact wrench loosens and tightens nuts and bolts.

When should you not use an impact wrench?

Don’t ever use an impact wrench if you aren’t sure that the threads are aligned properly on the object you plan to work on. This can cause serious problems.

What type of socket should be used with an impact wrench?

You want to use impact sockets as standard sockets can break or crack with that much pressure applied to them.

How long do impact wrenches last?

It depends on what brand and type you purchase. Air impact wrenches tend to be the most durable, but you must take care of them.

Is torque the same in electric, air, and cordless impact wrenches?

In general, the air impact wrench is going to provide the most power, with electric coming in second. From here, the cordless impact wrench provides the least because it is running on battery.

Is it possible to use an impact wrench as a drill?

You can with soft wood and light-gauge steel if you use a standard hex-shank drill bit.

Is it possible to use an impact wrench to loosen lug nuts?

Yes, you can use the impact wrench to remove a lug nut with the same force you put it on. If it is stuck or rusted, you might require more force to break it free.


Impact wrenches provide the everyday mechanic with a useful tool for tightening and loosening bolts. Ensuring you have the right tool and you understand how to operate is the key to your success.