Sockets are an extremely useful tool for tightening and removing nuts and bolts. Because they are available in a wide range of sizes, lengths, materials, and even different measurement systems, it’s understandable to be unsure which types and sizes you need.
To help you understand the differences between socket sets, I put together these Standard (SAE) and Metric (mm) socket set size charts and included intended set “best-use” information below the charts.
Common Standard Socket Sizes (Per Set)
The best socket set for you depends entirely on what you aim to accomplish. By the end of this article you should be confident about the sockets you’ll need, know which you won’t need, and understand your options.
First, the most common metric and standard socket set size charts.
|1/4” Set||3/8” Set||1/2” Set||3/4” Set||1” Set|
* Sets may include additional sockets.
Common Metric Socket Sizes (Per Set)
|1/4” Set||3/8” Set||1/2” Set||3/4” Set||1” Set|
|4 mm||10 mm||12 mm||26 mm||22 mm|
|5 mm||12 mm||13 mm||27 mm||24 mm|
|6 mm||13 mm||14 mm||29 mm||27 mm|
|7 mm||14 mm||15 mm||30 mm||30 mm|
|8 mm||15 mm||16 mm||32 mm||32 mm|
|9 mm||16 mm||17 mm||35 mm||36 mm|
|10 mm||17 mm||18 mm||36 mm||38 mm|
|11 mm||18 mm||19 mm||38 mm||41 mm|
|12 mm||19 mm||20 mm|
|13 mm||21 mm|
|14 mm||22 mm|
* Number of sockets per set may vary by brand.
Understanding the purpose of each set
Each socket set size and type is best suited for a specific type of work. Understanding what each set is good at, and what it can’t do, will help decide which set is right for you.
About 1/4″ socket sets: 1/4″ socket sets are designed for occasional, light duty use around the home. They are ideal for small tasks such as tightening hose clamps and removing bolts from small appliance panels.
1/4″ ratchets and spanners are not designed to apply much torque and may break when trying to remove a stuck bolt. Use gently. The smallest socket for standard 1/4″ sets is typically 3/16″, or 4 mm for metric sets.
About 3/8″ socket sets: 3/8″ socket sets are designed for all-purpose general duty use. They are capable of handling the nuts and bolts most commonly found on home outdoor power equipment.
3/8″ ratchets are more durable than 1/4″ ratchets and can deliver a reasonable amount of torque before breaking. They can free moderately stuck or rusted nuts and bolts with proper lubricant applied.
About 1/2″ socket sets: 1/2″ socket sets shine as a more durable version of 3/8″ sets, with one exception. They don’t include a few of the most common, smaller-sized sockets you are likely to need around the home.
The tradeoff is that the ratchets and spanners included in 1/2″ socket sets are typically more durable and can deliver more torque than their 3/8″ counterparts. The larger sockets in a 1/2″ socket set are useful in servicing the nuts and bolts commonly found on vehicles.
About 3/4″ socket sets: 3/4″ socket sets are an ideal continuation to 3/8″ socket sets. This is because the smallest sockets in a 3/4 set are most often slightly larger than the largest sockets in a 3/8 set, as you can see in the chart above.
Additionally, 3/4″ ratchets and spanners are capable of delivering enough torque to free all but the most stubborn bolts and can tighten bolts to a higher torque spec than smaller ratchets.
About 1″ socket sets: Most 1″ socket sets available online and at hardware stores are designed to be used with electric or air powered impact drivers. They don’t often have a ratchet or spanner included in the set.
Impact drivers deliver torque to the socket in short bursts, which helps loosen extremely tight or stuck bolts without breaking them. Impact sockets are made of chrome Vanadium (Cr-V) or other strong metals resistant to breaking. They are designed to withstand extreme amounts of torque.
My recommendation: A 3/8″ socket set is an ideal choice for the average person who will use it only occasionally around the home. It typically strikes the best balance between cost and utility, and it contains sockets for the most common bolt sizes, including 1/4″ and 10 mm.
What about Metric vs Standard, which should I choose?
Metric and Standard(SAE) are two different measurement standards, each favored by different countries. As far as choosing a socket set, what’s important to understand is that where you live in the world is irrelevant. Where the item(s) you are servicing were manufactured is what matters.
Example: when I service outdoor power equipment with newer small engines, I am almost always needing to use Metric sockets. This is because most new small engines have been manufactured in places like China, where the Metric system is the official measurement standard.
Conversely, when I service or restore vintage small engines, I am almost always needing Standard(SAE) sockets. Most older small engines in my area were manufactured in America, where standard(SAE) is the official measurement system.
It gets more complicated when servicing locally made equipment that is powered by a foreign made small engine. The result is equipment that has both Standard and Metric bolts.
You ultimately have two options. Either plan to acquire sockets of both types, or plan to use a socket size conversion chart to discover which socket of the opposite measurement system is most compatible.
The first option is more expensive and ads sockets to your tool box that you may never need, and the second option is more time-consuming and may not work on all nuts and bolts.
Is a 6 point socket better than a 12 point?
A 6 point socket has a hexagonal contact area that fits snugly over common hexagonal bolts. A 12 point socket has a contact area that resembles a star and can fit hexagonal bolts as well as less common square bolts. Besides the shape of the socket to bolt contact area, they are identical in appearance.
Functionally, a 6 point socket is capable of delivering more torque (force) than a 12 point socket while also being less likely to damage the bolt. The tradeoff, a 12 point socket is more versatile because it is compatible with a wider range of bolt types.
My suggestion: Unless you rely on your tools for work, or plan to use your sockets with an impact driver, stick with more versatile (and cheaper) 12 point sockets. You are more likely to need the versatility of a 12 point socket than the torque potential of a 6 point socket.
What about socket length? Deep vs Shallow
Deep sockets, also referred to as long sockets, are required for tightening or removing the nut from a long bolt. They are longer and able to fit over the shaft of the bolt.
Shallow sockets, often called normal or short sockets, may not reach a fastener if a bolt shaft is protruding from it. They are designed for tightening and removing easily accessible fasteners.
Additionally, Shallow sockets can access bolts in difficult to reach places where deep sockets may not have the clearance to fit. I use shallow sockets far more frequently than I use deep sockets.
Tip: When a shallow socket is not long enough to reach a fastener, it may be possible to access the opposite end of the fastener. Use a wrench to prevent the unreachable end of the fastener from spinning as you tighten or loosen it from the opposite side.
Do I need a combination socket set?
Combination socket sets include two different types of each socket. An example, a combination set may include a complete set of both Metric and Standard sockets or deep and shallow sockets of a single measurement type.
A combination socket set typically costs more than each individual set, but less than buying both sets individually. Most combination sets come with a handy molded storage case to keep sets well organized. These are the most common combinations.
Metric + Standard Combination Sets: This is the most common combination of socket sets, it includes Metric and Standard versions of each socket. This is the ideal combination set to choose if you want to be prepared with the right socket for either measurement system.
Deep + Shallow Combination Sets: A deep and shallow combination set is a good choice when you are confident you will only need to service fasteners of one measurement system (Metric OR Standard, not both). This type of set ensures you will have the right socket for short and long fasteners.
Multi-Size Socket Combination Sets: A multi-size combination socket set contains sockets of more than one drive size. This is a popular choice for the person wanting a wide range of socket sizes all neatly stored in one case.
The most common set sizes included in a multi-size combination set are the 1/4″ and 3/8″ sets, in both measurement systems, which means that four (or more) individual sets are packaged together.
Custom Socket Combination Sets (Create your own): With a good understanding of the benefits provided by each type and size of socket set, you can create your own set to best suit your individual needs. Buying sockets you’ll never use, in a set or individually, is not beneficial.
By being patient, and only buying individual sockets as you need them, you will end up with a custom set of your own. Not only will you save by not buying the sockets you don’t need, you’ll be able to wait for store sales to get the sockets you do need at a discount.
Another option to save money is to buy used sockets from local marketplaces, keep the sockets you need, and sell the rest to recoup some of your money. I often buy just 1/4″ and 10 mm sockets when I find them because I replace them so often while servicing small engines. Having spares of the sockets you use most is a good idea.
The downside of creating your own custom socket set is that it won’t come with a handy storage case, you’ll need to use a regular tool box for storage instead. Let me know if you have other preferences when it comes to socket sets.