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Historically, impact wrenches were predominantly pneumatic, or air powered, which left them squarely in the domain of professional mechanics. To run a typical 1⁄2-inch pneumatic impact wrench, an air compressor putting out close to 100 psi is typically required—and that’s a significant investment.
The good news is that battery-powered impact wrenches have gotten better as battery technology improves, which has brought prices down and made them viable alternatives to their pneumatic cousins. In fact, cordless impact wrenches have a tremendous advantage: mobility. Rather than being tied to a compressor with an air hose, these tools can easily go wherever they’re needed.
We tested a range of impact wrenches—from a heavy-duty, high-torque model down to a compact, medium-duty model—and subjected them all to the same challenges to identify their strengths and weaknesses. Read on for some buying advice, followed by our findings and reviews of the best impact wrenches we recommend.
Unlike cordless drill/drivers and impact drivers, which excel at drilling holes and driving screws, the cordless impact wrench is specially designed for tightening and loosening various hex-head bolts, nuts, and lag screws. It employs both rotational force and short-burst concussive blows for an unparalleled amount of power.
However, all that brute strength isn’t very useful if you can’t control the tool. Fortunately, cordless impact wrenches are extremely comfortable to use because the concussive blows smoothly transfer most of that high-energy torque directly to the fastener, not to your hand, wrist, or arm. As a result, the twisting motion—known as reactionary torque—that you feel when using an electric drill is virtually eliminated.
Torque measures the tool’s ability to drive in lag bolts or loosen stubborn nuts—the most important representation of power for an impact wrench. Most cordless drill/drivers produce about 50 foot-pounds of torque and the average impact driver delivers about 125 foot-pounds. By comparison, cordless impact wrenches can easily produce torque outputs of over 250 foot-pounds, which is more than enough muscle to power-drive the fattest lags and bust loose rusty, corroded nuts.
Generally speaking, the higher end (and pricier) cordless impact wrenches produce the greatest amount of torque. Torque output ranges from 225 foot pounds for sub-compact models up to 1,500 foot pounds of torque for the most powerful impact wrenches.
Impacts per minute (IPM) increase as revolutions per minute (RPM) increase. High RPM help drive nuts or bolts faster, while IPM kick in harder producing a faster rate of impacts as the resistance increases, thus transferring more torque to the drive head.
Impact wrenches produce massive amounts of speed and power, so being able to control it to avoid over tightening fasteners or spinning off lug nuts and sending them flying through your shop is key. Most impact wrenches have three or four speed settings that allow you to reduce the RPM and torque to lower levels to avoid these mishaps. Fancier impact wrenches have modes that automatically slow the wrench after it’s broken off a bolt to prevent spinning it off. Some have controls that allow you to dial in lower torques that simulate hand tightening or wrench tightening.
All things being equal, higher voltage gives you more power—but there are cases for lower voltage. With smaller batteries, 12-volt impact wrenches are more compact. This makes them good for smaller jobs, working overhead, or getting into tight spaces. Tools with 18 and 20 volts have less difference between them. Generally, 18-volt tools with advanced features and capabilities make them more versatile and easier to use.Amp hours (Ah) equals the number of amps that the battery discharges, continuously, for an hour. Think of amp hours like the volume of a gas tank—a bigger number equals more gas.
What are we talking about when we say size? The most common size impact wrenches are ½-inch drive models—those with a square anvil measuring ½ x ½-inch, that accepts ½-inch sockets. There are also smaller ⅜- and larger ¾-inch drive models, with the latter being for heavy vehicle maintenance, agricultural equipment, or other industrial uses.
Among half-inch impact wrenches, there are also tool body sizes—generally, full, compact, and sub-compact. If the tool isn’t labeled specifically compact or subcompact, you can assume it is a full-sized model. Full-size impacts have larger, longer tool heads, with beefier internals, and thus higher torque specs. They’re great for removing stubborn, rusted nuts and bolts. However, these bigger tools may not fit in the spaces where they are needed.
Compact and subcompact impact wrenches have shorter, less bulky, tool heads that fit into tight spaces better. Because they are smaller, they don’t have the high torque specs of the larger models, but they have more than enough for most assembly/disassembly tasks the average person might encounter. Their size and capability for common tasks makes compact impact wrenches incredibly versatile.
Every impact wrench on this list has been thoroughly vetted and evaluated by our test editors. We research the market, survey user reviews, speak with product managers and engineers, and use our own experience operating these tools to determine the best options.
We chose practical tasks that most people might need to accomplish with these impact wrenches. The first was removing and replacing lug nuts. Lug nuts removed were torqued to the recommended spec at 165 foot-pounds on a Ford F-250 Super Duty pickup truck—with compact wrenches, we removed them from a car torqued to a slightly lower spec of 150 foot-pounds. Standard sized wrenches were also used to remove, or break free, rusted nuts and bolts on an old piece of farm equipment.
While compact wrenches were used to remove and then replace new, 9/16-inch, grade eight bolts tightened to 200 foot-pounds. We evaluated them on performance, price, comfort, value, and versatility to determine the best impact drivers that meet the needs of a wide range of people.
Models like this Milwaukee are the heavy hitters when it comes to impact wrenches. They’re bigger, weightier, and torque-ier (1,400 foot-pounds for the M18 Fuel here). Removing lug nuts on our F-250 Super Duty was no challenge for this impact wrench. It barely hesitated breaking them loose.
With four modes, three different speeds, and a bolt removal mode, it’s easy to set the speed/torque for the job. And that bolt removal mode is a pleasure to use; it backs off the speed and torque once a nut or bolt breaks loose so that it doesn’t run off the end and go flying. When it came to the rusty old bolts on the farm equipment, the M18 broke them free without much effort, and using the bolt removal mode also helped prevent damage, spinning the nuts off over-rusted threads.
The M18 impact wrench is an effective tool for major jobs like heavy equipment repair, industrial maintenance and repair applications, or any other task with big, tough nuts and bolts.
Ryobi’s 18V One+ hits a price point that’s hard to beat, at the same time accomplishing everything we asked of it in testing. When we used it to remove lug nuts, it impacted for a little more than a second before breaking them loose and spinning them off. It only took slightly longer when we removed rusty bolts on a farm implement. We were also able to drive 6-inch lag bolts into pressure-treated lumber.
We found the three speeds were most useful when trying to avoid over-tightening fasteners. The lack of a brushless motor means we wouldn’t expect it to stand up to daily use, but this is a capable tool that helps get a lot of projects done around the house.
Using DeWalt’s Atomic 20V Max in a drive mode optimized for timber screws, we were able to drive lags bolts just a little faster than with the other models—having the highest torque specs also helped driving speed. That’s a lot of juice for a tool that measures less than 5 inches from tip to tail.
Like the Milwaukee, the Atomic 20V Max has a mode for bolt removal and fastening that prevents both runoff and over-tightening—plus two speed settings. When repeatedly tightening similar fasteners, like lug nuts, we were able to get a feel for getting them all within 5 to 10 foot-pounds of spec.
While the DeWalt was the most powerful, it was also the loudest model we tested. This compact impact wrench is great for working in tight spaces.
We could tell the DeWalt 20V Max XR was a beast when we picked it up. High-torque impact wrenches tend to weigh more because they have beefier components required to handle the forces involved in transferring all that torque. This is no exception, weighing 7.2 pounds with one of the two big 5-Ah batteries clipped to the bottom—the heaviest impact wrench in the test.
The weight does give the impression it’s well built and can take some abuse though. Removing the lug nuts on the F-250 Super Duty was seemingly effortless, the Max XR breaking them free in a fraction of a second. We tried it in all three speed settings, with the highest removing them the fastest. We had to get a feel for when to back off the trigger and let the tool’s momentum spin the nut off—do it too late and the nut could run off the stud at high RPM and fly out of the socket.
Working on the rusty farm equipment felt like a perfect job for the Max XR. The rusted nuts and bolts were no match for it—the only issue was being able to reach a couple of them because of the size of the wrench. DeWalt’s high-torque impact wrench would be a natural fit for auto, truck, or tractor repair out in the field or on the roadside.
You’re not going to find Ingersoll Rand (IR) tools in most big box, home improvement stores, but that doesn’t mean it’s not worth searching them out. IR tools are often found in industrial or commercial applications due to their reputation for robust performance and durable construction.
Their ½-in. High- Torque 20v Impact Wrench is a good example of this, with an all metal drivetrain, steel reinforced handle, and a whopping 1500 feet-pounds of nut busting torque. In fact, there wasn’t much in testing that could challenge the High-Torque’s capabilities—we didn’t have big enough, or rusty enough, hardware on our farm equipment. It differed from nearly all other multi-mode cordless impact wrenches in that it uses a dial mode selector on the back of the tool head. This means that the selector is always facing you—making it easy to see what mode it’s in and select a different mode.
The four modes include hand tight, wrench tight, half power and full power. Hand tight was great for snugging things like lug nuts up, while wrench tight cranks things down to around 100 feet-pounds, which is plenty tight for a lot of applications. IR’s ½-inch High Torque Impact Wrench would be ideal for daily or heavy use applications.
Flex’s ½-inch Mid-Torque Impact Wrench was able to handle every task in our test. It is well suited for auto maintenance and mechanical work, with plenty of torque for common operations.
Removing and fastening lug nuts tightened to 165 feet pounds was a quick, smooth operation. We used both bolt removal and auto-stop modes on the lug nuts, with removal mode cutting power once the lug broke free, to prevent spinning it at high speed right off the stud. A second pull of the trigger backed the nut off gently, while auto stop prevented over tightening nuts and fasteners—allowing us to go back with a torque wrench and tighten to spec.
The Flex also has three other mode settings that limit RPMs to 400, 1600, or 1200—so you can tailor speed to the task. Smaller and lighter than high torque models, this Mid-Torque impact is easy to handle and fits into more places you need to work.
While our testing geared more towards half-inch tools, Milwaukee’s M18 Fuel 3⁄8-inch mid-torque wrench never skipped a beat. We used a 1⁄2-to-3/8-inch adapter to remove and replace the lug nuts on our F-250 Super Duty pickup—a job it easily completed. We were also able to break free large, rusty nuts on our old farm equipment.
This impact wrench has four mode settings. The first three step up both RPM and IPM, with the third hitting max on both. The fourth mode (“drive control”) is the one we really like, though. When driving, it limits torque to 35 feet-pounds, so there is no risk of over-tightening fasteners. When removing a fastener, it starts off at full torque, then backs off the RPM when the fastener has broken loose, preventing spinning off at full speed.
The compact body and three LEDs on the face of the tool make it a good option in tight, dark spaces. This is a professional-grade tool, designed to stand up to daily use, but also an option for homeowners with frequent projects. We’ve turned to this tool several times since testing, as its size and torque are useful for a wide range of jobs.
The only subcompact model we tested, the Ridgid 18V, is smaller and lighter than the others. While we found it easy to handle overhead or in tight spaces, it couldn’t break free a 9⁄16-inch, grade-8 bolt tightened to 200 foot-pounds, although it did at 175.
Similarly, it struggled for us with a ½ x 8-inch lag bolt, but a smaller ⁵⁄16 x 4½-inch was not a problem. Despite this, the Ridgid was capable of tasks like removing lug nuts tightened to 150 foot-pounds. We were pleased with its bolt-tightening mode, which prevents over-tightening by shutting down at about 20 foot-pounds.
While the Ridgid won’t cut it for bigger jobs, it’s a good lightweight and compact option for lighter duty work.
Tony Carrick is a full-time freelance writer who specializes in technology, home improvement, DIY, home security, and outdoor recreation. He’s tested and written about everything from home security systems to power tools to gas grills. His product guides, how-to articles, and feature stories can be found in such publications as Bob Vila, Angi, U.S. News and World Report, Field & Stream, Futurism, and Switchful. When Tony isn’t writing, he can be found working on his latest home improvement effort at his home in North Carolina.
Brad Ford has spent most of his life using tools to fix, build, or make things. Growing up he worked on a farm, where he learned to weld, repair, and paint equipment. From the farm he went to work at a classic car dealer, repairing and servicing Rolls Royces, Bentleys, and Jaguars. Today, when he's not testing tools or writing for Popular Mechanics, he's busy keeping up with the projects at his old farmhouse in eastern Pennsylvania.
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