Impact Driver vs Impact Wrench: Which is Best for Your Needs?

  • March 8, 2019

frozen lug nut

There is nothing more frustrating than a nut frozen in place. All that is keeping you from reaching your goal is a piece of metal usually no bigger around than a quarter. But there it is, frozen in place and invulnerable to the straight-up torque of a traditional power driver.

Depending on how big it is, the best tool for the job is either the impact driver or the impact wrench. Both offer the kind of consistent concussive rotational blows to break loose stuck nuts. The effect is like placing a wrench around a stuck nut and hitting it with a hammer, except repeatedly and allowing the tool to do all the work.

Your needs should drive your choice

The first is lighter, more nimble and a lot less expensive. The question about the second is whether you can really justify investing the kind of money necessary to have its potential for the moments when you absolutely need it.

Your answer isn’t straightforward. Different people have different tool demands. So, we’ll run down the merits and drawbacks of both and leave to you the sticky issue of answering whether you’re okay with an impact driver or really need an impact wrench.

Comparative power: Inches to feet

It’s important to compare torque power between an impact driver versus an impact wrench. In drivers, it is measured in inch-pounds. Impact wrenches measure power in foot-pounds. While impact drivers often have big numbers, you can get a good idea how well it stacks up to torque wrenches by dividing their listed power by 12, the number of inches per foot. You can likewise get a good idea how much power an impact wrench has relative to impact drivers by multiplying its foot-pound rating by 12 to get its inches per foot rating. In general, impact wrenches are about twice as powerful as impact drivers.

In-between power

Impact drivers offer a useful option in between a traditional power driver and an impact wrench. They combine the small frame and ability to be nimble of a traditional driver with the slimmed-down torque power of an impact wrench.

impact driver

Image credit: Charles & Hudson, Flickr

For most homeowners, these offer plenty of power for most jobs. They specialize in, however, is their ability to drive screws into difficult surfaces. You can remove lug nuts from a car, but their quarter-inch adapter isn’t designed to accommodate the attachments to do it. If you want to remove a car’s lug nuts, make sure you find out the nut’s torque rating to see if your impact driver is suited for the job.

The other thing homeowners will find attractive about impact drivers is their price. They cost a little more than traditional drivers, but not anywhere in the same ballpark as an impact wrench.

Impact wrench for the biggest jobs

On the other hand, if you have a nut that is absolutely, positively stuck and that you absolutely, positively need to remove, you will absolutely, positively need an impact wrench. They are beyond the day-to-day needs of your average DIYer and are found most commonly in auto mechanic bays, factories and places where maintenance is conducted on heavy machinery.

These are designed purely to deliver power, and they have too much muscle to drive screws or do any of the light work impact drivers are designed for. The exception is lag bolts.

Compressed air no longer the only power option

Traditionally, they used compressed air to build torque, but especially in the last decade power sources have broadened.

You can even find cordless, battery-driven impact wrenches. These offer the mobility of a driver with the power of a wrench. Because it operates by battery rather than compressed air, they usually have less power. You might also be concerned about the battery dying, although it’s less of a concern because when you use an impact wrench it’s for short spurts.

Conclusion

There’s really no simple way to choose an impact driver or an impact wrench. That choice is ultimately driven by what you need and what you can afford.

Most people will find an impact driver adequate for their needs, even beyond their basic design to drive in screws. That includes a cordless impact driver. Technology has progressed well enough the last few years to provide them enough torque to loosen lug nuts for most cars, and for a battery that won’t die halfway through a job.

Before you take that as a sign that you’re good with a driver, you’ll want to consult owners manuals of anything you’ll need to loosen. It could be that you’ll actually need something with the power of an upper-end impact driver or an impact wrench.

If you know you’ve got really heavy work to do or just don’t want to be bothered with the question, an impact wrench is designed to handle the hardest, most difficult jobs there are. They just have too much muscle to drive in screws.

About the Author Adam Harris

Hi there! My name is Adam and I write for HealthyHandyman. I have a great passion for writing about everything related to tools, home improvement, and DIY. In my spare time, I'm either fishing, playing the guitar, or spending quality time with my beloved wife. You'll also often find me in my workshop working on some new project!