How Much Torque Do I Need in an Impact Wrench?

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Last Updated on December 24, 2022 by John Smith

Choosing the right impact wrench for your needs can be like solving a puzzle. With so many options, it can be difficult to make the right decision.

Some brands invest heavily in advertising to boost sales, while others prioritize quality. But how can you be sure which impact wrench is best for you?

But, how are you supposed to know which impact wrench is better for your specific needs?

Well, one of the main things you gotta have clear is what torque output you need your next impact wrench to provide and that’s exactly what we’ll discuss in this article.

Let’s begin.


How Much Torque Do I Need in an Impact Wrench?

We rounded up 4 factor that will determine exactly how much torque you need for your next impact wrench:

  1. Torque Needs
  2. Budget
  3. Portability
  4. Anvil Size

Torque Needs

We all know that torque is very important in an impact wrench.

But, what is the torque output actually?

An impact wrench’s torque level is the measure of rotational force applied to the fastener – such as a lug nut or bolt – through the anvil.

This measure is critical, as it affects the speed of work and determines the tool’s suitability for different projects, which typically require different torque levels.

It’s also important to know that different workers have different needs regarding torque levels.

Some may only need to fasten one or two lug nuts a week, while others may need to remove hundreds of rusty nuts and bolts a day.

All these tasks require different torque levels, so it’s important to take a few minutes to write down what you plan to use the impact wrench for and find out the required torque levels. This method will give you a better idea as to what are your torque needs for your impact wrench.

For instance, for general home maintenance or changing tires, an impact wrench with 300 ft/lbs of torque is sufficient.

On the other hand, for heavy work such as loosening or tightening hundreds of nuts and bolts a day, changing truck tires, or doing exhaust/suspension work, an impact wrench with more than 1000 ft/lbs of torque is more suitable.

Budget

When considering your torque needs, you should also take your budget into account.

I mean, you won’t be able to get a $500 impact wrench’s torque output if you have less than $200 to spare.

In my experience, taking inflation into account, here is what torque you can expect from an impact wrench depending on its price:

  • $150 to $200: You’d get an impact wrench with 200 to 300 ft-lbs of torque, suitable for light applications (e.g. general home maintenance)
  • $250 to $400: You’d get an impact wrench with 600 ft-lbs of torque, perfect for mechanics working on medium-sized vehicles
  • $450+: You’d get an impact wrench that outputs more than 1200 ft-lbs of torque, which is perfect for workers looking to work on heavy applications

Portability

Simply put, the rule is that a bigger impact wrench will output more torque.

Why?

Well, a bigger impact wrench means that the tool will be able to have bigger and more potent internal components (e.g. stronger brushless motors) that will output more torque as a result.

Additionally, the larger form-factor allows for a bigger anvil, which increases the strength of the hammer mechanism and increases torque. 

So, if portability is a priority a smaller impact wrench should be chosen, as it will be less powerful but more portable. However, if more torque is desired, a larger impact wrench should be chosen.

Anvil Size

Other than the size, an impact wrench’s anvil size will be a huge factor that determines its torque outputs.

In fact, the larger the anvil size, the more torque the impact wrench will produce because a larger anvil means more surface area for the tool’s hammer mechanism to develop. This is critical for increasing torque levels.

So, if you need more torque (1,000 ft-lbs or more), go for a 3/4 impact wrench, whereas if you don’t, a 1/2 impact wrench (with a smaller anvil) might be the best choice.


What Does an Impact Wrench Do?

The primary function of an impact wrench is to loosen or tighten fasteners such as nuts and bolts.

Impact wrenches, in contrast to impact drivers, are known for providing higher levels of torque, allowing users to easily remove or fasten hundreds of nuts and bolts and even work on jobs that require higher levels of torque (e.g. changing truck tires).

Normally, impact wrenches are preferred to do the following tasks:

  • Automotive work: Impact wrenches are used to change tires and remove rusty nuts and bolts stuck in suspension or engines systems
  • Construction work: Here, impact wrenches are utilized to remove and fasten nuts and bolts on large machinery and general construction projects
  • DIY projects and general home maintenance: Even though impact wrenches output higher levels of torque, they are preferred by home owners to make DIY projects easier and faster

Frequently Asked Questions

Here are some of the most frequent questions asked about impact wrenches and their torque levels.

How much torque do I need in an impact wrench to remove lug nuts?

The amount of torque needed to remove lug nuts is generally around 80 foot-pounds, and most impact wrenches with a torque output of greater than 80 foot-pounds should be able to do the job.

However, if the lug nuts are particularly rusty or stuck, then you may need an impact wrench with a torque output of at least 150 foot-pounds, as the additional torque will be necessary to break the rusted bond between the nut and bolt.

Is 400 Nm torque good for impact wrench?

400 Nm is about 300 foot-pounds of torque and even though this isn’t the highest torque an impact wrench can output, it will be enough to cover the basics.

Meaning, you’ll be able to work on:

  • General home maintenance
  • Removing and fastening nuts and bolts for medium sized vehicles
  • Small construction projects

What size impact wrench do I need for automotive work?

The size of impact wrench you’ll need for automotive work will highly depend on three factors:

  • Vehicle size: If you’re working on a small or medium-sized vehicle, a 1/2-inch impact wrench will provide enough torque to get the job done. However, if you intend to work on larger vehicles, such as trucks, a 3/4 should provide enough torque to allow you to work efficiently.
  • Budget: If you have a budget of $150 to $200, a 1/2 impact wrench is your best bet (at least if you prioritize quality overall). If you want to spend more than $500, you could get a 3/4 impact wrench, which is significantly more powerful.
  • Portability: A bigger anvil, means a bigger motor and a bigger form-factor of the impact wrench. So, if portability is a big priority for you, then you should go for a 1/2 impact wrench, as it has a smaller size. However, if torque is important for your job (e.g. mechanics), then going for a 3/4 impact wrench should be your best bet
Author
Hi, I’m John Smith, a proud husband, and father of two little beautiful girls. After a long time of thinking I made up my mind to build a website around my passion.. helping people who need smart advice from handymen with years of experience.

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