Milwaukee M18 FUEL™ 1/2" Impact Wrench

Buying Guide: How To Choose A Cordless Impact Wrench

Cordless Impact WrenchAn over-tightened or rusted nut or bolt that’s stuck can be one of those things that makes you realize you need to add a new tool to your kit. One of the best models for the job is a cordless impact wrench. This useful equipment has more torque than most drills and it can take care of a stuck nut or bolt in a matter of minutes, saving you time and frustration. Find out more about this handy tool in our cordless impact wrench buying guide.

How A Cordless Impact Wrench Works

Inside the tool is a rotating mass. A cordless impact wrench uses batteries to generate power. The motor builds up energy using the rotation and then pushes it into an anvil that’s located at the end of the tool. This creates an enormous amount of torque, more than can be produced by any human. The mass, which is shaped like a hammer in the best cordless impact wrenches, continues to rotate, so the operator only feels a tiny amount of the impact.

99895722-741F-472F-989D-BDD20F8E5A6AAs well as generating so much torque, cordless impact wrenches are very precise, which makes them ideal for numerous applications. It’s much safer to use this type of power tool when working on a construction site, or when securing lug nuts on a wheel, as opposed to doing it by hand. Even though all impact wrenches function in the same way, if you perform a cordless impact wrench comparison, it’s easy to notice that they do have many differences.

Cordless Impact Wrenches Versus Other Tools

As you plan to buy a cordless impact wrench, it’s important to understand that while it generates plenty of torque, it’s usually less than comparable devices that use compressed air. Because of this, a cordless impact wrench is an excellent option for smaller jobs. It’s ideal for a home workshop where space is at a premium. Because a cordless impact wrench uses rechargeable batteries, it can be a little heavier than the corded variety, but does offer much greater mobility, especially in areas too tight or remote to accommodate a power cord.

What To Look For In A Cordless Impact Wrench

2F94F58F-38AF-4A61-8771-A2C3997DD8F0When choosing your new cordless impact wrench, there are a few things you should consider. The first thing to decide is the brand. If you have other cordless tools, it’s a good idea to choose a cordless impact wrench that uses the same battery pack and charger as your other devices. It’s also a good idea to spend a little time doing a cordless impact wrench comparison. Some of the high-end models offer additional features such as adjustable torque settings, which cuts out the need to use a manual torque wrench.

Shapes And Socket Size

Cordless impact wrenches come in two body styles: inline and pistol-grip. The inline style of impact wrench looks a lot like a large screwdriver, with a grip behind the hammer and anvil. The pistol style is shaped like a handgun, and the grip rests underneath the motor. Cordless impact wrenches also feature a selection of socket sizes designed to fit nuts and bolts of different sizes. The following table shows what socket sizes work with each impact wrench shape. Inline wrenches work best for jobs where you’re working in tight spaces and simply can’t fit a pistol-type impact wrench. If you plan to work on machinery, especially cars, then an inline impact wrench is a must-have tool.

While pistol impact wrenches are bulkier, their grip style is more ergonomic to prevent strain on your hands, which in turn allows you to work for longer periods without fatigue. Some of these models can equip side handles which let you use your weight for greater leverage and to maintain a proper working angle. If you don’t need the special fit of an inline wrench, a pistol-style impact wrench is usually the ideal choice.

Socket Size

Impact Wrench Shape

1/4-inch Both inline and pistol
3/8-inch Mostly pistol, but also works with a specialized inline style known as a butterfly wrench
1/2-inch Pistol
3/4-inch Pistol
1-inch Pistol and a T-shaped inline featuring handles opposite the anvil

Larger socket sizes are also available, up to a 2 inches. However, bolts that large are typically found in very large scale jobs that require heavy-duty impact wrenches with power needs greater than that you find in a cordless wrench.


Jobs that require the power of an impact wrench usually entail using them for many operations over an extended period. Ergonomic handle grips and anti-vibration measures help to reduce work-related strain. Additionally, you should pick a cordless impact wrench with just the right amount of power necessary to perform the job properly. A smaller motor tends to mean fewer vibrations, which in turn lessens the physical strain.


Look for design enhancements, such as all-metal construction for the gear housing or high-strength plastic overmolds, which helps to prevent damage due to impacts or being dropped. Impact wrenches with brushless motors have fewer moving parts, which means that there’s less of a chance of components breaking down, and maintenance is easier to perform.


Regardless of the style of cordless impact wrench that you choose, or what its socket size is, the most important feature to consider is how much torque it generates. When performing a cordless impact wrench comparison, look at the maximum torque that each one is capable of creating. Many of the best cordless impact wrenches feature multiple torque settings making them much more versatile than those with only one torque setting. Setting he torque down only to what’s needed lets your battery work longer and prevents overtightening.

When compared to many other power tools, cordless impact wrenches are quite specialized in what they do. Large nuts and bolts may not need to be removed or tightened as often as smaller screws. But when you do need to adjust one, a cordless impact wrench will save you both time and energy. They can also loosen and tighten nuts and bolts much more accurately than hand tools such as sockets and ratchets, which is critical when it comes to working with larger bolts or on machinery.


  • The Wrencher

    March 15, 2017 at 12:16 pm

    Mostly I like the part Socket Size and Impact Wrench Shape. Great Job you did in this blog. Well all information is very nice and useful.

  • John Stewart

    June 19, 2019 at 9:59 am

    I have been reading a lot of posts on factors to consider when buying a cordless impact wrench and this is by far the best of them all.
    Thanks for sharing

    • Acme Tools

      June 29, 2020 at 8:25 am

      Hi Ed, Thank you for your question. The tools have different uses and you must decide which is best for your needs. A 3/8″ impact is better for smaller low torque applications and it is typically lighter weight. A 1/2″ impact is typically for larger applications, has more torque, and is heavier. It all depends on your needs.

      Thank you, Acme Tools

  • Paula

    May 12, 2022 at 7:32 am

    How do I know what size or torque I need to change the blades on my lawn mower? I want to buy one to do this can anyone give me some help? I have an air compressor or I have a battery power too. What is the most cost effective? I don’t forsee a lot more I will use it for but a nut or bolt here or there and regular changing of blades on mower. Thank you.

    • Acme Tools

      May 12, 2022 at 9:45 am

      Hi Paula. Generally speaking walk behind mower blades should be tightened to 40-50 ft lb and riding mower blades should be tightened to 70-90 ft lb. If you have your owners manual for the mower it should be stated there for your specific unit. Once you have that information you can make an educated decision on what type of impact wrench is best for your situation.

      Thank you,
      Acme Tools


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