Ratchet Socket Sizes Guide

Fasteners, ratchet, and socket wrench sets allow you to tighten or loosen various bolt and nut sizes.

Understanding ratchet drive sizes, socket sizes, and more will ensure you select the proper tools for your projects. Ratchet and sockets are available in various sizes and will deliver increased leverage and efficiency compared to an adjustable wrench or set of conventional wrenches.

The ratcheting mechanism lets you tighten or loosen a fastener without removing the socket from the bolt/nut each turn. In our guide, you can learn more about all the different sizes of ratchets and which sockets are available.

By the end, you’ll know the common ratchet sizes and the different ratchet socket sizes you may need. (Read Standard Size Spark Plug Socket)

Types of Sockets

There are a few main socket types available:

• Standard 12-point socket – The most common type of socket with 12 splines or points that grip the flat sides of hex fastener heads. Available in both 6-point and 12-point configurations.
• Deep socket – Extra deep sockets are used when the bolt or nut is recessed in a hole or surrounded by obstruction. The deep socket cups the fastener head while allowing clearance.
• Impact socket – Heavy duty sockets made of hardened chrome alloy steel for use with impact wrenches. Withstands extreme torque of power tool.
• Specialty sockets – Designed for specific applications like spark plugs, oxygen sensors, lug nuts, etc. Often, they have unique shapes to fit special fasteners. (Learn How Many Sizes Of Torx Bits Are There)

How Ratchet Sockets Work

Ratchet sockets attach to the square drive on the end of various ratchet wrench sizes handles. The size of the square drive mating surface dictates the different ratchet sizes compatible with that socket.

For example, when matching a socket to a ratchet, you have limits. Such as a 1/4” drive ratchet can only accept 1/4” drive size sockets and accessories.

The section that attaches to the socket has a female hex or spline cavity that grips the head of the fastener.

When the handle of the ratchet wrench is turned, the ratcheting mechanism allows the socket to tighten or loosen the bolt/nut without resetting the socket on the fastener each turn.

The direction switch on the ratchet handle controls whether turning the handle clockwise or counter-clockwise will tighten or loosen the fastener.

Socket Size Chart

Sockets come in various metric and SAE sizes to fit various bolt and nut types and sizes. The size stamped on the socket shows the size of the fastener head it fits.

Common metric sockets in order include 10mm, 12mm, 14mm, 17mm, 19mm sockets and larger 21 and 22mm socket sizes. SAE sizes include 1/4”, 5/16”, 3/8”, 7/16”, 1/2”, 9/16”, 5/8”, 3/4”, etc.

SAE Socket Sizes

Size	Bolt/Nut Diameter
1/4″	0.250 inches
5/16″	0.3125 inches
3/8″	0.375 inches
7/16″	0.4375 inches
1/2″	0.500 inches
9/16″	0.5625 inches
5/8″	0.625 inches
11/16″	0.6875 inches
3/4″	0.750 inches
13/16″	0.8125 inches
7/8″	0.875 inches
15/16″	0.9375 inches
1″	1.000 inches

Metric Socket Sizes

Size	Bolt/Nut Diameter
6 mm	6 mm
8 mm	8 mm
10 mm	10 mm
12 mm	12 mm
14 mm	14 mm
16 mm	16 mm
17 mm	17 mm
18 mm	18 mm
19 mm	19 mm

Most Common Drive Sizes

The drive size dictates the strength of the socket and the size ratchet handle required. Common drive sizes include:

• 1/4” drive: The size of the socket head size here makes it suitable for light-duty applications. This small socket size will be suited to the most small fasteners.
• 3/8” drive – Versatile common sizes are available for many general automotive repairs.
• 1/2” drive – Large drive for heavy-duty repairs.
• 3/4” drive – Extra strength from these fasteners sizes and types are used for the most significant bolts/nuts. These are used in heavy equipment. (Learn How To Use Ratchet Wrench)

Shallow vs. Deep Sockets

Shallow sockets provide enough depth to grip the standard exposed bolt and nut heads. Deep sockets are extra deep to allow use where the fastener is recessed in a hole or flush against a surface.

• Shallow Sockets: Depth is 1-1.5x the size. i.e., 10mm shallow is around 10-15mm deep.
• Deep Sockets: Depth is 2-3x the size. i.e., a 10mm deep socket has 20-30mm depth. (Read Light Bulb Socket Sizes Chart)

SAE to Metric Socket Conversion Chart

Available in standard (SAE) and either metric, so here you can see the different socket sizes and how a wrench and socket size relate to each other. (Read SAE To Metric Conversion Calculator)

SAE to Metric Conversion Chart
SAE Socket Sizes	Metric Socket Sizes	Similar Socket Size
5/32”		5/32” and 4mm are almost the same
	4mm
	4.5mm
3/16”
	5mm
	5.5mm
7/32”
	6mm
1/4”
	6.5mm
	7mm
9/32”
5/16”		5/16” and 8mm are similar
	8mm
11/32”
	9mm
3/8”
	10mm
13/32”
	11mm	7/16” and 11mm are similar
7/16”
15/32”		15/32” and 12mm are similar
	12mm
1/2”
	14mm
9/16”
	15mm	19/32” and 15mm are similar
19/32”
5/8”
	16mm
21/32”
	17mm
11/16”
	18mm
21/32”
	17mm
11/16”
	18mm
23/32”
	19mm	3/4” and 19mm are similar
3/4”
25/32”
	20mm
13/16”
	21mm
27/32”
	22mm
7/8”
	23mm	29/32” and 23mm are similar
29/32”
15/16”
	24mm
1”

Types of Ratchets, Sockets, and Accessories

Socket sizes range from small to large, and don’t just use a standard socket for the fastener. So, a ratchet set includes the ratchet handle plus a variety of metric and imperial socket sizes and accessories. This covers most of the ratchet size chart and keeps your socket wrench sizes in order:

Here are some of the main components:

1. Socket

The socket has a hex/spline cavity that fits onto the bolt head or nut. Comes in varying sizes, depths, and drives.

2. Pass-Through Socket

A pass-through socket has a hole allowing you to fit a long bolt through the center. This will enable you to access bolts that would otherwise hit the inside wall of a standard socket head.

3. Spark Plug Socket

A spark plug socket has a rubber insert that grips the porcelain insulator of spark plugs for easy removal and installation. The hex size fits the spark plug metal base.

4. Impact Socket

Heavy-duty chrome vanadium steel sockets are designed specifically for use with impact wrenches. Withstand extreme torque levels.

5. Socket Adapter

Adapters to allow different drive size sockets to be used on one ratchet. For example, a 3/8” to 1/2” adapter lets you use a 1/2” drive ratchet with a smaller 3/8” socket instead.

6. U-Joint Adapter

A U-joint adapter provides an offset and articulation for angled access to crowded bolts when using a socket and ratchet. It’s helpful when you need a socket, yet right-angled sockets won’t fit.

7. Socket/Ratchet Extension Bar

Extension bars allow you to extend your reach with the end of the socket for hard-to-reach bolts. The added length helps generate leverage and torque. Locking extensions help keep your socket from falling into tight spaces.

8. Torque Wrench

A torque wrench allows tightening bolts and nuts to the correct socket torque specification to help avoid overtightening.

9. Breaker Bar

A breaker bar provides extreme leverage to loosen very tight bolts and nuts. The ratchet head rotates freely, allowing force in either direction.

This covers some of the most common pieces found in a socket set. Certain sets include other useful accessories like nut drivers, hex bits, etc. (Learn How To Determine Allen Wrench Size)

Ratchets and Sockets vs. Wrenches

The right socket used with a ratchet offers some advantages over traditional wrenches:

• Speed – The ratcheting mechanism provides quicker tightening/loosening without resetting the tool each turn.
• Access – Sockets can reach into recessed areas better than some fixed wrenches. Extensions provide even more reach.
• Versatility – A single ratchet can be fitted with any size socket needed for the job. It’s more convenient than a complete set of fixed wrenches.
• Torque – Ratchets allow improved grip and leverage compared to slippery wrench handles and are easier to deliver high torque.

However, conventional wrenches still excel in certain situations:

• Clearance – A low-profile wrench can access tight confines where a socket won’t fit.
• Simplicity – Basic adjustable wrenches are inexpensive options. No sockets to lose or misplace.
• Feel – The slim profile of a wrench allows an excellent “feel” for delicate tasks. May strip bolts with excessive torque.

For most tasks, a ratchet and socket set provides the best blend of convenience, versatility, and torque. But wrenches still serve a purpose in tight spots. (Find the Best Ratcheting Wrench Set)

Deep Socket Length and Special Features

Choosing the proper socket configuration will make your projects easier:

• Shallow vs. Deep – Shallow sockets for exposed nuts/bolts. Deep sockets for recessed fasteners.
• 6-point vs. 12-point – 6-point sockets grip better. 12-point allows sockets to be used at more angles.
• Metric vs. SAE – SAE for domestic vehicles. Metric for imports. Sets often include both.
• Drive Size – Larger drive sizes allow more torque for stuck bolts. Smaller sizes are better for tight areas.
• Specialty Sockets – Pass-through, spark plug sockets, impact sockets, etc. Suit specific applications.
• Extensions/Adapters – Add reach and flexibility. Allow sockets to be used at odd angles or far from the fastener.

Selecting sockets with ideal attributes for your particular repair will make the job easier. Investing in a comprehensive set provides all the options you need. (Find the Best Price Socket Sets)

Final Thoughts: Common Drive Sizes for Socket Set

With this guide, you should now understand the various ratchet and socket configurations, sizes, and accessories available.

The most versatile socket sets include both SAE and metric sizes, all common drive sizes, shallow and deep sockets, extensions, adapters, and specialty sockets. This provides all the options needed for automotive work and general DIY jobs.

Invest in a comprehensive socket set to get all ratchet sizes and sockets from a reputable brand like Gearwrench, Sunex, Proto, or Snap-On.

With proper care, a quality ratchet and socket set can deliver a lifetime of service. Don’t forget a socket organizer tray, as these help keep all your wrench or socket sizes in order. (Read Socket Sizes in Order from Smallest to Largest)

FAQs About Different Types of Socket Types

What are the most common socket sizes I’ll need?

For general DIY use, focus on obtaining sockets in the following SAE sizes: 1/4”, 5/16”, 3/8”, 7/16”, 1/2”, 9/16”, 5/8”, 11/16”, and 3/4”.

These will fit most standard domestic nuts and bolts. Supplement with metric sockets in the 10mm to 19mm range, which covers imports.

How do I know which drive size to use?

Use the 1/4” size of the drive socket for tight areas and small fasteners, and the 3/8” drive socket size are designed to be used for general repair. Use 1/2” drive for high torque applications like suspension, drivetrain, wheels, etc.

Why choose 6-point vs 12-point sockets?

• 6-point sockets allow for a more secure, snug fit on the flat sides of fasteners. This provides a better grip and reduces rounding off bolts.
• 12-point sockets can be used at more angles (every 30 degrees), which allows access in tight areas. But the points can round off bolts more easily.

What are impact sockets, and when should I use them?

Impact sockets are made from hardened steel and engineered with impact wrenches. Use impact sockets if using an impact driver to prevent cracking.

How can I determine SAE vs. metric socket sizes?

Different types of ratches and socket, and for SAE, use inches and fractions of an inch – 1/4 “, 1/2 “, 3/4”, etc. Metric sockets have a variety of sizes in millimeters – 10mm, 12mm, and 17mm. Domestic cars use SAE, while imports often use metric, so you’ll need different size sockets and different size ratchets when working on various cars. (Learn How To Measure Socket Drive Size)

What’s the difference between shallow and deep sockets?

Shallow sockets provide enough depth for exposed fasteners. Deep sockets are extra deep to allow access to where the nut or bolt head is recessed or obstructed.

SAE to Metric Conversion Chart
SAE Socket Sizes	Metric Socket Sizes	Similar Socket Size
5/32”		5/32” and 4mm are almost the same
	4mm
	4.5mm
3/16”
	5mm
	5.5mm
7/32”
	6mm
1/4”
	6.5mm
	7mm
9/32”
5/16”		5/16” and 8mm are similar
	8mm
11/32”
	9mm
3/8”
	10mm
13/32”
	11mm	7/16” and 11mm are similar
7/16”
15/32”		15/32” and 12mm are similar
	12mm
1/2”
	14mm
9/16”
	15mm	19/32” and 15mm are similar
19/32”
5/8”
	16mm
21/32”
	17mm
11/16”
	18mm
21/32”
	17mm
11/16”
	18mm
23/32”
	19mm	3/4” and 19mm are similar
3/4”
25/32”
	20mm
13/16”
	21mm
27/32”
	22mm
7/8”
	23mm	29/32” and 23mm are similar
29/32”
15/16”
	24mm
1”