Spark Plug Socket Sizes (with Drawings)

Standard Spark Plug Socket Size

Each vehicle owner of either car or motorbike should have a spark plug socket – they may come in handy when you need to fix your vehicle parts or something in your house. Find out here which size of spark plug socket is compatible with your vehicle.

What is a Spark Plug Socket?

What is a Spark Plug Socket

A spark plug socket is a type of socket specifically designed for removing old spark plugs and installing new ones. It enables the user to grip onto the spark plug without damaging any nearby wires or threads. It operates in the same way as regular sockets but may also benefit from a swivel extension bar which enables it to reach into compact spaces without causing damage to other wires.

They are ideal for working with small elements and completing delicate tasks because they are better equipped for this compared with standard sockets.

They work by gripping onto the tip of the spark plug, and then the user twists the socket to either tighten the spark plug or loosen it. This means the spark plug socket can work well for both removing an old spark plug as well as fixing a new spark plug into place.

What is the Standard Spark Plug Socket Size?

spark plug socket sizes

Spark plug sockets come in a range of sizes because spark plugs themselves come in a range of sizes. The socket you use will need to be compatible with the size of your spark plugs.

Typically, when buying a spark plug socket, you will get a set of various sized sockets, which means you can simply try the socket on your spark plug to see if it’s the right size and if it isn’t, then try the next size up or the next size down.

See also  12v Car Batteries - Sizes & Weight

This is also handy because if you get a new vehicle or want to help out a neighbor with their vehicle, then you will always have the right spark plug socket size to hand.

However, if you would rather buy an individual spark plug socket, then this is a possibility too, but you will need to know exactly which size is going to be compatible with your vehicle.

The most common spark plug socket sizes in the US are ⅝ inch and 13/16 inch, though many more sizes are available. There is not one single standard spark plug socket size.

Typical Spark Plug Socket Sizes

Newer road vehicles

The majority of newer vehicles with four wheels, such as cars and trucks, will need a spark plug socket that is ⅝ inches in size. This is the most common size of spark plug socket, and as such, it may also be considered the standard spark plug socket size, but it won’t work with all spark plugs. In millimeters, the size of this spark plug socket is 16mm.

Older vehicles

If you have an older vehicle or a vehicle with an older engine, then the spark plug socket size you need will likely be 13/16 inches. This is the second most common size of spark plug socket since many older vehicles are still in use. In millimeters, the size of this spark plug socket is 20mm.

Small engine cars

Most small engine cars will require the same size of spark plug socket as new cars, which is ⅝ inches or 16mm. The exception to this is small engine BMWs, which use a different size of spark plug socket than other small engine cars, which you can find out about later in this list.

See also  Understanding Your Parking Space Size: A Comprehensive Guide


Motorcycles tend to have spark plugs that are more uniform in size, making it easier to repair almost any motorcycle with just one size of spark plug socket. The standard size of spark plug socket for motorcycles is ¾ inches. In millimeters, the size of this spark plug socket is 19mm.


If you need to replace a spark plug on your lawnmower, then the size of socket you need will be ¾ inches. This is the same size of socket used on motorcycles, so you could use one socket interchangeably if you own a lawnmower and a motorcycle. In millimeters, the size of this spark plug socket is 19mm.


Tractors will require a spark plug socket size of ⅞ inches or 22mm for those using the metric measurement system.

Aviation vehicles

Aviation vehicles like airplanes and helicopters will typically all require the same size of spark plug socket to change the spark plugs. This socket size is, like tractors, ⅞ inches or 22mm.

Small engine BMW’s

If you have a BMV vehicle with a small engine, then you will likely need a different size of spark plug socket compared with BMW’s with larger engines and the vast majority of other small engine vehicles. Small engine BMWs require a spark plug socket in an 11/16 size, or 18mm.

Ford engine vehicles

Vehicles that have a Ford engine will need a different size of spark plug socket than most others. The size required will be 9/16 inches or 14mm.

Newer Asian engine vehicles

Vehicles that are made by Asian manufacturers or which have Asian-made engines will need a spark plug socket that is 9/16 inches or 14mm. This is the same size of socket used by vehicles with Ford engines.

See also  Parallel Parking Dimensions and Guidelines (with Illustrations

Types of Spark Plug Sockets

You will be able to find spark plug sockets with various features and extensions, but essentially all spark plug sockets can be separated into two categories. These are:

Magnetic spark plug sockets

A magnetic spark plug socket benefits from a tiny magnet inside the depth of the socket head. This magnet will grip onto the spark plug when you are removing it or installing a new one, ensuring that the spark plug doesn’t get accidentally dropped and lost during the job.

Rubber grommet spark plug sockets

This type of spark plug socket has a small rubber grommet fitted deep into the socket. It is there to secure the spark plug in place and prevent any damage from occurring, which could lead to faults. Possible damage includes the spark plugs getting bent or scratched. The rubber grommet acts as a barrier to ensure that no such incident happens.


Baron Cooke has been writing and editing for 7 years. He grew up with an aptitude for geometry, statistics, and dimensions. He has a BA in construction management and also has studied civil infrastructure, engineering, and measurements. He is the head writer of

Leave a Reply

Your email address will not be published. Required fields are marked *