Socket Size Chart: Easily Find the Size or Conversion you need

If you’re looking for an easily reference socket size chart, you’re in the right place! Check out the table of contents below to quickly find the chart you need. A socket tool is one that attaches to a rachet or wrench to allow much more efficient work while you turn a nut or a bolt.  You can easily loosen or tighten without having to reposition the tool as you would with a wrench. Because the socket will fully enclose the nut or bolt head, you will also have much better grip and therefore increased torque than you would with an open jaw wrench. Once you’ve used one, you’ll never go back!

Ratchets and wrenches in drawer of toolbox

Due to the many different shapes and sizes of fasteners available today, it is likely that even the most comprehensive socket set will not offer every possible combination.  With that in mind, we will be looking at a socket size chart, types, and how you can determine the the best fit for your current needs.

Types of Socket Sizes

There are two different types of socket sizes – the metric type and the standard type.  The standard type may also be referred to as the SAE (Society of Automotive Engineers) or imperial system.  In socket sets, they will be all positioned in order from smallest size to largest.

In order to achieve the best fit with your socket and a nut or bolt, you will need to determine their size and use the corresponding socket size type, either Standard (SAE) or metric.  For example, an SAE nut will need to be used with an SAE socket to ensure that you get the most correct fit.

Similarly, a metric bolt should be used with a metric-sized socket. Alternatively, you can use a socket size chart to convert SAE sizes to metric sizes, and vice versa, if you find yourself without the exact type you need.

This means that you’ll be able to use SAE and metric sockets interchangeably with most kinds of nuts and bolts.

Socket Drive Sizes

Metric and Standard (SAE) sockets come in three available drive sizes:  1/4 inch, 3/8 inch, and 1/2 inch.  The measurement refers to the size of the square used to attach the to socket to a wrench or a ratchet. The smaller sockets are typically the most helpful for tight spaces, while the larger drive sockets handle more torque to allow easy ability to fully loosen or righten.

Types of Socket Sets

In addition to having different size types, socket sets also come in different fastener sizes and components based upon the application.  We will briefly cover a few of the most common here in the list below.

Impact socket sets are designed to be used with power tools, whether electric or pneumatic air driven, in applications such as automotive repair and maintenance.  They can be forged from thicker alloys to prevent shattering and coated to prevent corrosion.

Deep socket sets are typically available in smaller sets or as individual attachments, as these are less frequently used.  A good example of this is a spark plug, where the socket is deep enough to reach the seated spark plug.

Hex socket sets are also called six point socket sets and are designed to fit over a six sided nut or bolt, and these are the most common type of socket.

Twelve point socket sets offer twice as many inner contact points as the hex socket set, which can make it easier to place the socket over different fasteners, as well as allow for a square headed nut or bolt, which cannot be used with a hex socket.

SAE or Standard Socket Size Chart

Below is a table of SAE (Standard) socket sizes. These refer to SAE tools, sockets, and bolts.

SAE Socket Sizes
1/4” Drive3/8” Drive1/2” Drive3/4” Drives1” Drives

Converting SAE Sizes To Metric Sizes

If you need to convert metric sizes from standard sizing, you can use the socket size chart below to help with that.

Bear in mind that metric sizes don’t always relate completely to standard (SAE or imperial sizes), but there are different socket sizes from both methods of sizing that correlate quite closely to one another.

When converting SAE sizes to metric sizes, you will need to convert them between inches and millimeters. This chart can help you to convert sizes in regard to wrenches, sockets, and other tools as well.

Standard To Metric Sizing Conversions
SAE SizesMetric SizesSimilar Socket Sizes
5/32”4 mm5/32” and 4 mm are almost the same
 4.5 mm 
 5 mm 
 5.5 mm 
 6 mm 
 6.5 mm 
 7 mm 
5/16” 5/16” and 8 mm are almost the same
 8 mm 
 9 mm 
 10 mm 
 11 mm7/16” and 11 mm are almost the same
15/32” 15/32” and 12 mm are almost the same
 12 mm 
 13 mm 
 14 mm 
 15 mm19/32” and 15 mm are almost the same
 16 mm 
 17 mm 
 18 mm 
23/32”19 mm3/4” and 19 mm are almost the same
 20 mm 
 21 mm 
 22 mm 
 23 mm29/32” and 23 mm are almost the same
 24 mm 
 25 mm 
 26 mm 
 27 mmexactly the same
 28 mm 
 29 mm 
 30 mm 
 31 mm 
 32 mm 
 33 mm 
 34 mm 
 35 mm 


We hope this article has allowed you to quickly find the appropriate tool using the socket size chart. Remember to bookmark this page and come back to it any time that you need to work out a conversion for your sockets or other tools.  If your conversion needs are specific to wrenches, please reference our Wrench Sizes Chart.

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