What is the difference between an Allen wrench and a hex key?

What is the difference between an Allen wrench and a hex key?


Have you ever assembled the furniture? Or maybe you spend hours in your garage? Then you definitely used this tool. Some call it a hex key, others - an Allen wrench. 

For more than a century, people have been using these instruments, they are affordable and popular among many users the world over, including professional mechanics as well as those who need these tools for home use. 

Nowadays, there are many instruments to choose from. This article is aimed to help you figure out the difference between an Allen wrench and a hex key.

The short answer is “there is no difference”. Really, these two names can be used interchangeably. Keep reading if you want to know why.

Why are they called “hex keys”? 

These instruments are essentially L-shaped wrenches that have six sides. They are utilized to drive hexagon-shaped recessed holes. Greek “hex” means “six”. Hence the name.

Why are they referred to as “Allen wrenches”?

At the beginning of the 20th century, William G. Allen patented a cold drawing process for making hex socket set screws. Wrenches to turn these screws would make Allen famous. “Allen” is a registered trademark, however, even wrenches from other manufacturers are sometimes called Allen wrenches.


These handheld tools are compact, portable, and lightweight, you can take them with you wherever you need to go. In addition, using them reduces fatigue, increasing your productivity. There are so many advantages, just get the right tool for your specific application!

Choose the best tool for you!

On Mega Depot, you can find items that come in an array of sizes (measured by across-flats - the distance between the opposite ends of the flat side). Please note that if your Allen wrench is bigger than it should be, the fastener or instrument may be damaged. There are tools from various manufacturers, choose the right one for you! It is possible to buy them separately or in sets.

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