Impact Driver Vs. Impact Wrench: Which Is The Right Tool For You?

If you are a DIY kind of person, you’d need to build your toolbox for your projects or for basic car maintenance. Two of the common tools that you’d come across and need are an impact driver and an impact wrench. While many folks might think that they are the same thing due to their names, they are actually two different tools used for different purposes, despite sharing some similarities. So what is the difference between an impact driver and an impact wrench? Which one should you use for which job? Read on to find out. 

Impact Driver Vs. Impact Wrench: What Are They For?

Impact Drivers

Both impact drivers and impact wrenches can be found in the tool chests of mechanics anywhere. You can decide which of these two impact tools to use based on the drive style. 

An impact driver or impact drill is a screwdriving specialist. When you’re loosening and tightening fasteners which require higher rotational torque and which require a driver bit such as slotted, Phillips, square, or Torx, you’d need an impact driver for the job. For light hex head fasteners, you might need a socket adapter for the job.

An impact driver is also capable of drilling holes in hard materials using drill bits that have a compatible hexagonal shank. One note though, if you want to drill masonry, a hammer drill would be a better tool than an impact driver. 

Here, many folks may wonder why you can’t just use a regular cordless drill to do all these. While a cordless drill can technically perform the same jobs as an impact driver, a drill is far less powerful and efficient, and thus would also exhaust you very quickly. While a cordless drill only uses rotational power to get the job done, an impact driver is much more powerful, thanks to the use of rotational power coupling with percussive power. This combination makes driving in screws or fasteners much quicker while you’d have to exert less force.

Impact drivers are easy on your wrists, but a cordless drill would cause more stress and fatigue.  Say if you need to screw in five screws, using an impact driver would allow you to finish in half the amount of time it would take using a regular cordless drill. 

Impact Wrench

An impact wrench or an impact gun is a tool used for fastening and loosening nuts and bolts. It’s also used for tightening and loosening longer, thicker fasteners such as timber screws. Instead of inserting a bit into the head, you’re using a socket to grab around it.

An impact wrench is an excellent tool for driving lug nuts and fasteners that demand very high rotation force. For instance, when you take your vehicle to an auto repair shop to change the tires, you will see the mechanic using an air-powered tool that makes the ‘brrr’ sound.That is a pneumatic impact wrench.

The Type of Jobs They’re Used For

In general, an impact driver and an impact wrench are used for different projects. All in all, while even DIY amateurs can get a lot of use out of impact drivers, an impact wrench is a specialty tool and only used in larger-scale construction projects, for maintenance of machinery, and in auto repair shops. 

So an impact driver is a tool that more people would need. In contrast, you’d most likely only need an impact wrench if you know that you are going to be maintaining your vehicle in your own garage in the near future. The powerful impact wrenches will make DIY car maintenance much easier.

Impact drivers are used on the vast majority of carpentry and home improvement projects. Because of this, impact drivers are commonly found in the tool box of amateur DIYers and professionals alike.

Meanwhile, an impact wrench is a specialty tool and only used in certain special professions, due to their tremendous power. Further below, we will provide more details as for the power output of these two tools. In automobile repair shops, they are used to quickly pop out or tighten the bolts and nuts used on cars and trucks without exhausting the mechanic’s arm and wrist. 

That said, if you chose to use an impact wrench for home projects, the tremendous power of the impact wrench can actually be a disadvantage. For instance, if you use an impact wrench on the wrong kind of screw, such as a very short one, you run the risk of over-tightening the screw. You might need a special impact wrench that features internal attachments to prevent overtightening, but they are more expensive and harder to find than the regular type.

Should you need both for DIY home improvement projects and car maintenance in your own garage, it’s recommended by seasoned DIYers that you grab both from the same brand. This approach is beneficial as you build out your collection, since you can save money by adding other bare tools and use the same battery in both tools.

Power Output (Torque)

Regarding the power or torque output, in most cases, you get much more power from an impact wrench than you would from an impact driver. That said, both tools have different classes of product with different power ranges. You might find that some of the most powerful impact drivers in the 18-volt/20-volt class are even more powerful than the most compact and thus least powerful impact wrenches, especially in the 12-volt class. But when excluding compact impact wrenches from the equation, you almost always get more power from impact wrenches.

Do note that the power output of an impact driver is often measured in inch-pounds whereas the torque of an impact wrench is measured in foot-pounds. An inch-pound (in-lbs, or pound-inch, lbs-in) is the torque of one pound of force applied to one inch of distance from the pivot, and is equal to 1⁄12 foot-pound. A foot-pound is the amount of turning force applied to move one pound a distance of one foot around an axis at a radius of one foot. One way to remember: Just like you do with linear inches and feet, divide by 12 to convert in-lbs to ft-lbs or multiply by 12 to convert ft-lbs to in-lbs if you want to compare values.

For impact drivers, anything over 1,600 in-lbs (125 ft-lbs) is a good primary tool for professional use, and there are many models that exceed 2,000 in-lbs of torque (167 ft-lbs) for extra demanding jobs.

Meanwhile, the minimum output for impact wrenches is around 100 ft-lbs (1200 in-lbs) of torque and the upper limit is well over 1,000 ft-lbs (12,000 in-lbs). That is more than 7 times the amount of power of impact drivers. 

For reference, an impact wrench with 200 ft-lbs of torque should be powerful enough for changing tires on a passenger car. As for other car maintenance and repair jobs, a mechanic should be able to accomplish everything needed using a mid-torque impact wrench, which has at least 400 ft-lbs of torque.

When buying an impact wrench, you should pay attention to the specifications to make sure the one you’re considering has enough power for what you need. Most manufacturers provide the “nut-busting torque”, or how much fastening force an impact wrench can remove. This is higher than the actual fastening torque, so do double check.

Impact wrenches have three power levels, that is compact, mid-torque, and high-torque. Although there’s no set power level that defines each class, they should give you a broad idea of the power level when choosing the right tool for your task. For most DIY car owners and even construction pros, all you’d ever need is a compact and maybe a mid-torque. If you need one for replacing the transmission, start with a 18V/20V max mid-torque 1/2-inch impact wrench.

Speed

The speed of the best impact drivers on the market tend to max out around 3600 RPM, sometimes more with the most heavy-duty ones. As for impact wrenches, the least powerful cordless model would max out at 2000 RPM, but for pneumatic (air) impact wrenches, a good mid-torque model can easily reach 8,000 RPM or higher with the best ones.

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Drive Style 

Another major difference between these impact tools is the drive style. Impact drivers use a 1/4-inch hex collet that accepts 1/4-inch hex shank bits. Impact wrenches typically use a square drive that you attach a socket to. 

Impact wrenches cover a much larger range of performance levels and being a specialty tool, they offer more specialty versions for different professions, for instance, the 7/16-inch hex impact wrenches used by utility workers. Generally 3/8-inch drives are more common for compact models, though some of the smallest impact wrenches come with a a 1/4-inch square drive.

If you need more powerful impact wrenches, 1/2-inch drives are probably the most common size. Every professional that uses impact wrenches would have one of this size.

Moving up in performance, 3/4-inch and 1-inch drives would offer you extreme power for certain demanding jobs. These powerful tools are mainly industrial tools and heavy equipment tools, and might be so powerful that unless you work in specific trades, you probably would never need them.

Impact wrenches also come in different styles, suc as pistol grip, right angle, stubby (with short head for reaching into tight spots), ratchet (low-power version to replace hand ratchets) and utility (7/16-inch hex collet).

Size and Weight

There are some impact drivers and impact wrenches built on the exact same foundation with different drives. Other than those, if we’re comparing products from the same manufacturer, an impact driver is most likely more compact and lightweight than a cordless impact wrench. Pneumatic impact wrenches can be lighter, though.

With impact wrenches, the more powerful one is, the bulkier and heavier it usually is. The drive size can also clue you in. 1/4-inch drives are only found on compact models while 1/2-inch drives are more common on the larger and heavier mid and high-torque impact wrenches. Even larger and heavier are the 3/4-inch and 1-inch drives.

An important note on adapters. There are adapters that allow your impact wrench to accept 1/4-inch bits, as well socket adapters and nut driver bits for an impact driver for working with hex head fasteners. But the fact that there’s an adapter for the intended job doesn’t mean it’s right for every application. A lack of power might not get the job done, or worse, strain the tool’s motor and possibly cause it to burn up, but too much power can break bits and shear fastener heads.