Standard Wrench and Socket Sizes in Order

In the years since, I've completely forgotten where some of the most common box end, open end wrench and socket sizes fit in. After a quick search yielding no real good results containing all of this information, I've decided to create a reference SAE (inches) + Metric (mm) page and size chart for myself and others to refer to. So without further ado, here are the results.

Take 7/16" and 9/16" for example; two of the most frequently used sizes in automotive work. The 7/16" wrench fits common 1/4"-20 bolts, while the 9/16" wrench is standard for 3/8"-16 bolts. Back in the day, I used these so often that I could grab them blindfolded. But over time, those size to bolt relationships start to fade from memory, which is exactly why I decided to put together a comprehensive chart.

Standard Wrench Sizes Chart | Socket Sizes in Order

Standard Wrench and Socket Sizes Chart with Metric Conversions: The following chart lists the most common standard wrench and socket sizes, including their corresponding sizes one step smaller and larger, as well as the metric equivalents. For easy reference, you can also download the SAE Size and Metric Equivalent Conversion Table as a PDF file.

Standard Wrench Sizes In Order | Smaller or Larger | SAE to Metric equivalent

Below is a list of commonly used SAE (Imperial) Standard and Metric wrench and socket sizes in ascending order up to 2 inches. For each size, I also mention one size smaller (step down) and the next size bigger or larger (step up), along with their equivalent size in Metric or mm.

Standard Wrench Sizes in Order | (Smaller than) | (Larger than) | (Equal to in mm):

• 1/4" (1/4" is one size smaller than 5/16") (5/16" is one size bigger than 1/4") (Equal to 7 mm in Metric)
• 5/16" (5/16" is one size smaller than 3/8") (3/8" is one size bigger than 5/16") (Equal to 8 mm in Metric)
• 3/8" (3/8" is one size smaller than 7/16") (7/16" is one size bigger than 3/8") (Equal to 10 mm in Metric)
• 7/16" (7/16" is one size smaller than 1/2") (1/2" is one size bigger than 7/16") (Equal to between 11-12 mm in Metric)
• 1/2" (1/2" is one size smaller than 9/16") (9/16" is one size bigger than 1/2") (Equal to 13 mm in Metric)
• 9/16" (9/16" is one size smaller than 5/8") (5/8" is one size bigger than 9/16") (Equal to between 14-15 mm in Metric)
• 5/8" (5/8" is one size smaller than 11/16") (11/16" is one size bigger than 5/8") (Equal to 16 mm in Metric)
• 11/16" (11/16" is one size smaller than 3/4") (3/4" is one size bigger than 11/16") (Equal to 18 mm in Metric)
• 3/4" (3/4" is one size smaller than 13/16") (13/16" is one size bigger than 3/4") (Equal to 20 mm in Metric)
• 13/16" (13/16" is one size smaller than 7/8") (7/8" is one size bigger than 13/16") (Equal to 21 mm in Metric)
• 7/8" (7/8" is one size smaller than 15/16") (15/16" is one size bigger than 7/8") (Equal to 23 mm in Metric)
• 15/16" (15/16" is one size smaller than 1") (1" is one size bigger than 15/16") (Equal to 24 mm in Metric)
• 1" (1" is one size smaller than 1-1/16") (1-1/16" is one size bigger than 1") (Equal to 26 mm in Metric)
• 1-1/16" (1-1/16" is one size smaller than 1-1/8") (1-1/8" is one size bigger than 1-1/16") (Equal to 27 mm in Metric)
• 1-1/8" (1-1/8" is one size smaller than 1-1/4") (1-1/4" is one size bigger than 1-1/8") (Equal to 29 mm in Metric)
• 1-1/4" (1-1/4" is one size smaller than 1-5/16") (1-5/16" is one size bigger than 1-1/4") (Equal to 32 mm in Metric)
• 1-5/16" (1-5/16" is one size smaller than 1-3/8") (1-3/8" is one size bigger than 1-5/16") (Equal to 34 mm in Metric)
• 1-3/8" (1-3/8" is one size smaller than 1-7/16") (1-7/16" is one size bigger than 1-3/8") (Equal to 35 mm in Metric)
• 1-7/16" (1-7/16" is one size smaller than 1-1/2") (1-1/2" is one size bigger than 1-7/16") (Equal to 37 mm in Metric)
• 1-1/2" (1-1/2" is one size smaller than 1-9/16") (1-9/16" is one size bigger than 1-1/2") (Equal to 39 mm in Metric)
• 1-9/16" (1-9/16" is one size smaller than 1-5/8") (1-5/8" is one size bigger than 1-9/16") (Equal to 40 mm in Metric)
• 1-5/8" (1-5/8" is one size smaller than 1-11/16") (1-11/16" is one size bigger than 1-5/8") (Equal to 42 mm in Metric)
• 1-11/16" (1-11/16" is one size smaller than 1-3/4") (1-3/4" is one size bigger than 1-11/16") (Equal to 43 mm in Metric)
• 1-3/4" (1-3/4" is one size smaller than 1-13/16") (1-13/16" is one size bigger than 1-3/4") (Equal to 45 mm in Metric)
• 1-13/16" (1-13/16" is one size smaller than 1-7/8") (1-7/8" is one size bigger than 1-13/16") (Equal to 47 mm in Metric)
• 1-7/8" (1-7/8" is one size smaller than 1-15/16") (1-15/16" is one size bigger than 1-7/8") (Equal to 48 mm in Metric)
• 1-15/16" (1-15/16" is one size smaller than 2") (2" is one size bigger than 1-15/16") (Equal to 50 mm in Metric)
• 2" (2" is the largest SAE wrench size) (Equal to 51 mm in Metric)

Common Bolt Sizes & Matching Wrenches

Knowing which wrench fits which bolt can save you time and frustration. Below is a guide to common SAE and Metric bolt sizes along with the correct wrench sizes to use.

As you can see, many metric and SAE sizes overlap. If you’re in a pinch, some close metric equivalents can be used on SAE bolts and vice versa.

7/16" and 9/16" Close Calls in Metric Equivalents

While many SAE sizes convert neatly to metric, a couple of sizes sit right on the edge of two close metric options. Take 7/16" for instance; it converts to about 11.11 mm, which makes both 11 mm and 12 mm sockets potential fits. In practice, 11 mm is usually the better choice for a snug fit, but some users report 12 mm also working on worn or variably manufactured bolts.

Another commonly debated size is 9/16", which equals roughly 14.29 mm. This puts it between 14 mm and 15 mm in the metric world. While 14 mm is closer, it can feel a bit tight depending on the bolt. Meanwhile, 15 mm may fit a bit loose, making 9/16" unique in how it straddles that metric line. When precision matters (especially with torque or rusted fasteners) it's usually best to stick with the actual SAE size.

These 'borderline' conversions are a good reminder that although SAE and metric tools often overlap, having the exact match in your toolbox can save a lot of time and a few knuckles.

Types of Wrenches and Sockets

In addition to knowing the size you need, it's important to understand the types of wrenches and sockets available. Common types include:

• Standard Wrenches: These are the traditional, open ended wrenches you're probably used to seeing in any toolkit.
• Box Wrenches: These are closed loop wrenches that fit securely around the nut or bolt, providing more torque and reducing the chance of stripping.
• Socket Wrenches: These are used with interchangeable sockets and allow for a greater range of motion, making them ideal for tight spaces.
• Torque Wrenches: A special tool that ensures fasteners are tightened to a specific torque value. This is particularly important for automotive work.

Socket and Wrench Sizes and Use Case

The socket and wrench sizes listed above are standard for most mechanical and automotive tasks. Here's a breakdown of where these sizes are typically used:

• Small SAE Sizes (1/4" to 1/2"): These sizes are commonly used in precision applications, such as small machinery, electronics, and automotive tasks like bicycle and motorcycle maintenance.
• Medium SAE Sizes (9/16" to 1-1/4"): These sizes are frequently found in automotive work and general mechanical tasks. Many hand tools, like ratchets and wrenches, are designed for these sizes.
• Large SAE Sizes (1-5/16" to 2"): These larger sizes are typically used for heavy machinery, large automotive applications (such as truck engines), and industrial equipment.

In addition to size, the type of measurement system also plays a crucial role in selecting the right tools:

• SAE (Society of Automotive Engineers): This system is primarily used in American-made products and vehicles.
• Metric: More common in European, Asian, and modern industrial machinery, the Metric system has gained widespread use in recent years.

Tool History & Fun Facts

Ever wondered where wrench sizes came from? Here are some interesting facts about SAE and Metric measurements:

• The SAE system was developed primarily for American made vehicles and machinery.
• Metric tools became widely used in the U.S. after the 1980s, as foreign car manufacturers gained popularity.
• The adjustable wrench (also known as a "Crescent Wrench") was invented in 1892 by Johan Petter Johansson.
• The phrase "righty tighty, lefty loosey" is a mnemonic for remembering the standard threading direction.
• Some aircraft use a mix of SAE and Metric fasteners, making proper tool selection critical for aviation mechanics.

Next time you pick up a wrench, remember that you're holding a piece of engineering history!

Frequently Asked Questions (FAQs)

Here are some commonly asked questions regarding metric vs standard SAE wrench and socket sizes:

What is the difference between SAE and Metric wrench sizes?

SAE (Society of Automotive Engineers) wrench sizes are measured in inches and are mostly used in the United States, especially for older or American-made vehicles. Metric sizes, on the other hand, are measured in millimeters and are more commonly used worldwide.

Can I use a Metric wrench on an SAE bolt?

In some cases, Metric and SAE sizes are close enough that one can work for the other in a pinch. For example, a 13mm wrench is very close to a 1/2" SAE. However, for best results and to avoid stripping, it’s recommended to use the exact size match.

How do I convert SAE sizes to Metric?

Use a conversion table like the one provided above. As a general rule: 1 inch = 25.4 mm. So, divide the SAE size by 1 and multiply by 25.4 to get the Metric equivalent.

What are the most common wrench sizes?

Common SAE sizes: 7/16", 1/2", 9/16", 5/8", 3/4". Common Metric sizes: 10mm, 13mm, 15mm, 17mm, 19mm. These sizes are frequently used in automotive and home repair projects.

What type of wrench should I use for tight spaces?

A socket wrench with a swivel or a ratcheting box wrench works best for tight or hard-to-reach spaces. These tools provide flexibility and reduce knuckle-busting frustration.

SAE to Metric Wrench and Socket Sizes in Conclusion

Whether you're working with SAE or Metric tools, this wrench and socket sizes conversion chart can be your best friend when it comes to getting the right size every time. It saves you time, eliminates confusion, and ensures your project stays on track. Let me know if you find it helpful or if you have a size matchup I missed.

Happy wrenching!