Spark Plug Socket Size Chart

Almost each and every spark plug comes in different HEX size. Hex refers to the socket or the diameter in the center of a spark plug which is used to turn the spark plug and screw it down or undo it. There are a lot of options out there, but in general, you need 14,16,18,21 mm sockets with both 12 and 6 point configuration. Almost all new vehicles including cars, motorcycles and even garden machines use these spark plugs. There are additional sizes as well, but they are mostly not in the use or they are available in some rare cases, such as older BMW cars. Since the 90s, car manufacturers started using 16-21 spark plugs in most cases and we can still see those sizes appear in the mechanic workshops and among the hobbyists. All sockets you are planning on using should be made from premium materials and they must withstand pressure.

Spark plug size in inchesSpark plug size in mmSocket neededAplication
5/8165/8-16mmScooters, motorcycles, smaller cars
13/162013/16Cars
3/4193/4Lawn mowers/Small engines
183/8Motorcycles
9/16149/16Ford, Newer asian cars
18mm bi hex11/16BMW/MINI
11/16811/16Older BMW
7/87/8Rare
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