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Allen Key vs Allen Wrench

A photo of allen key and allen wrench in collage.

Even though many people think an Allen key and an Allen wrench are the same things, there are actually several differences when it comes to an Allen key vs an Allen wrench. Check out our detailed information to help you understand the similarities and differences between the two of them.

Many people view an Allen wrench as being the same thing as an Allen key but that is not really true. The two are very similar but also have differences between them. So what are the similarities and differences between the two?

We take an in-depth look at each one in the article below so that you will have a better understanding when it comes to an Allen key vs an Allen wrench.

What is an Allen Wrench?

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An Allen Wrench is an L-shaped tool that is shaped like a hexagonal key, also called a hex key. An Allen wrench comes in very handy when you are attempting to put hex screws into wood, plastic, or even metal. I remember the first time someone asked me to get them an Allen wrench out of the toolbox.

It was my dad and it took me a long time to find a wrench. When I handed it to him, he said that was not an Allen wrench, went to the toolbox himself, and fetched one out. I had no idea that an Allen wrench actually looks nothing at all like a regular wrench since it is L-shaped.

The Allen wrench got its name from the company that registered the trademark before these tools which is the former Allen Manufacturing Company that was located in Hartford, Connecticut.

In today’s world, the company that produces Allen wrenches is the Apex Tool Group (ATG) and company officials would prefer that they be referred to by their standard name of a hex wrench instead of an Allen wrench or Allen key but many people, especially in the United States, still refers to them as Allen wrenches.

I now own several Allen wrenches and Allen keys after realizing that I need these several times each year for various projects around my house.

What is an Allen key?

This is a stainless steel set of allen wrenches in a red holder.

An Allen key is basically just like an Allen wrench because in many cases, they look alike but so people refer to both of them as either an Allen key or an Allen wrench. The most common ones are L-shaped, like the Allen wrench, which is why it can be a little confusing to people.

An Allen key is also known as a hex key, can be purchased as a singular tool or you can purchase a hexagon key set of different sizes.

Allen Key vs Allen Wrench Similarities

An Allen Wrench set and an Allen key set resemble each other which is the reason people think they are the same. They are both used to tighten or remove a hexagonal screw that is located inside of a hex socket and the ends of them are similar to that of a Phillips screwdriver with six sides to fit into the screw or hex fastener.

Both Allen wrenches and Allen keys, also known as hex keys, are considered to be hand tool essentials since they are the only type of hand tools that can fit in the hex bolt head of a hex screw.

In other words, they both act as the most popular and convenient tool for getting into hard-to-reach places to remove or tighten a hexagonal bolt or hexagonal screw that is located inside of a hexagonal socket. They also both apply a similar amount of torque so they act as a torque wrench when working with smaller bolts and screws.

This is the reason that I could not, for the life of me, figure out what to do with a daybed I was taken apart, along with several other things around my house. I was attempting to use an electric drill to reach the screws inside of the hexagonal socket and also tried doing the job with a Phillips screwdriver, to no avail.

Also, after putting together numerous pieces of furniture recently that boast the same type of hexagonal socket, I am very grateful for my Allen Wrench as well as hex key set.

Both an Allen key and an Allen wrench are great and extremely important to have on hand at your home or garage in your toolbox when working inside tight spaces.

Allen Key vs Allen Wrench Differences

This is a dark metal set of various sized allen wrench.

There are differences between an Allen key and an Allen Wrench in the fact that when it comes to each of them, there are different versions that are offered for you to use on your projects and the fact that you can purchase Allen keys in a whole set and even on an actual key ring or in a plastic case yet Allen wrenches are more often purchased one at a time.

There are different types of Allen wrenches, there are many of them, including ones that have a flat head end or a ball end. There are ball-end hex keys available, too, but they are smaller and a little more difficult to work with.

The ball end allows for better control and the screw head will fit into the Allen head screws or an Allen bolt easier since it is a straight shot to it rather than the curve of L-shape.

You can also purchase an Allen wrench with a much longer handle than an Allen key and even in a T-shape instead of the L-shape that hex key is known for. The T-shape allows for much better control since it provides a long arm, also, and is super easy to use when working on projects, such as repairing a car and needing to read a set screw that is in a blind spot.

An Allen wrench is made of chrome vanadium steel and is more durable and will last longer than a hex key set that features black oxide. They also are available as metric wrenches which are sometimes needed for certain projects and you can measure the end of your specific Allen wrench ahead of time.

Each ball driver comes in different metric sizes to fit into the proper hexagonal cross-section.

An Allen key can act as a Torx screwdriver that works much better on Torx screws than an Allen wrench and will easily fit into the hex head of a hex socket screw. Sometimes they are even referred to as a Torx key.


What is the smallest Allen key size?

There are a variety of sizes available when it comes to Allen keys, as well as Allen wrenches, and the smallest ones are metric and measure 0.71mm and 0.89mm.

Why is an Allen key called an Allen key?

Both the Allen wrench and Allen key are produced by the Allen Manufacturing Company which is the reason for the name Allen.

Is an Allen wrench a hex key?

Allen wrenches are also referred to as hex key wrenches or hex keys, feature a hexagonal cross-section that will fit into a variety of different machine screws and set screws that have hexagonal-shaped recessed holes.

How do I know my Allen key size?

When it comes to most Allen wrenches, the size is stamped clearly on the side of it. If the size of your Allen key has rubbed off over time, you can use a hex key chart or Allen key chart to locate the correct size of your socket head.