TOP 3 BEST Spark Plug Gap Tools


The distance between the contacts of the central and side electrodes of the spark plugs is called the gap. The spark power is primarily depend on its magnitude. Larger it is, the better the ignition of the combustible mixture, that directly affects the operation of the power unit. However, there is a second side. With a large distance, in order to get such a gap, a certain voltage is a must; and the value of it is limited by the capabilities of the ignition system. However, in order to regulate and expose it, you need to measure it. For this you need to use special devices, they are used to measure gaps between spark plugs. They are different, today we will show you how to choose such a spark plug gap tool, what to look for during the selection and describe several creme de la creme models.

What are spark plugs?

It is a device for igniting the fuel-air mixture in a wide variety of heat engines. It consists of steal body, an insulator and a central conductor.The modern ones can have a built-in resistor between the contact terminal and the central electrode. 

There are two-electrode and multi-electrode spark plugs. Starting with the latter, multi-electrode last much longer since they use several electrodes for ignition. In addition, they are made of copper or platinum. Copper is a standard option, but those that are made of platinum are considered more reliable and more stable. In addition, there’s an option of gasoline engines which are conventionally divided into “hot”, “cold”, “medium” ones according to the operating mode, depending on the thermal characteristics of the plug. 

The performance on the spark plugs affects the quality of the ignition and the combustible mixture. The large distance between the contacts provides a high power spark discharge, which increases the likelihood of ignition. If the distance is not that big, the spark will be of low power, which may not be enough to ignite the combustible mixture. Both of these will affect the engine performance.

How to check spark plugs

You can check the condition of any spark plugs by yourself at home (below we’ll provide information on it). 

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Benefits of using

As you can see, the gap between the spark plugs plays a big role in the operation of your car. If you want your vehicle to deliver proper performance, you should monitor it from time to time. Using this device you can independently keep the size of the gap to the breeder’s option. In addition, this device will help you correctly align the clearance on new spark plugs if you decide to change them yourself. 


There are three popular types of this device – Feeler Gauge, Ramp Style Gauge, Wire-Loop Style Gauge. 

They differ from each other by shape. The first option resembles the sun from blades arranged in a circle.  It is very accurate and can be used even with older car models. However, there are some people that use just such a measuring device.

 The second type resembles a coin made of steel in shape. Such device is the most convenient and cheapest but the least accurate of all options. Today it is the most popular option among car owners, as it is quite cheap, reliable and convenient.  Wire-Loop Style Gauge is similar to the previous one, but has a circle of wires. This option is the most accurate in the readings, but can not be used in older models of spark plugs.

Things to Watch Out For

First of all, pay attention to the measuring system.  There are options with inches and millimeters. It should be convenient and understandable for you, so as not to engage in the conversion of millimeters to inches and vice versa. The quality of the construction is also of great importance. Choose the device that is made of quality material. As for decent options, they are made of steel, as it is strong and will last you a long time. Of course, over time, it may become rusty, but if you choose the option of a trusted brand, it will last for a long time. 

The numbers on the sensor should be readable and not disappear as time goes by. Therefore, it is better to choose the device with by laser. Such sensors will last longer since the numbers simply will not be erased. However, besides this, pay attention to the ease of use. 

Safety tips

Working with it, be aware of safety and handle any spark plug gap carefully since even falling may cause the clearance to decrease. Spark plugs must be cleaned with alcohol before adjusting clearance.  In addition, you may notice soot on spark plugs: it can be black and gray. If you see a black soot, it means that your spark plug has burned out and you need to change it. 

Product review

This option is made of stainless steel and is very convenient to use. You can perform various works with it. It has a range  0.02 to 0.1-Inches (0.50 – 2.5-Millimeters). Due to this fact, it can be called very flexible and convenient option. Dimensions are 1 x 1 x 1 inches (2.54 cm). Item Weight is 0.8 ounces (ca. 30 g).

• Flexibility and convenience
• This option is very easy to use since it has a very clear scale
• Made entirely of steel, which ensures
• In addition, this option is very cheap.
• Not the most accurate option.

Very high quality and easy to use. It requires from 0,20 inch to 0,80 inch. This is a very large range, which includes cars of various models, both old and new. Due to this, it is considered very versatile. Please note that it has a recess. With this recess, the electrodes can be adjusted.  Has a pocket-clip what makes this measuring instrument even more convenient to use. The dimensions are 7.7 x 3.4 x 0.5 inches (1.27 cm). As for the weight, it is 0.8 ounces (ca. 30 g).

• It has a convenient measurement scale
• Thanks to the handle it can be used in various
• It is suitable for various models of automobiles since it has a wide range for measurements
• Has a pocket-clip
• Not the most accurate option.

Convenient and versatile option. The sizes range from 0.025-0.55 -inches. Pay attention it includes Built-In Gap Adjuster, what makes this option even more convenient to use. The option is very comfortable and durable. Steel construction ensures quality and durability. Dimensions are 2.2 x 2.8 x 6 inches (ca. 15 cm). Item Weight is 1.44 ounces (ca. 54 g).

• Steel construction ensures quality
and durability
• Not the most accurate option
Product DimensionsWeightRangeAdvantage
CTA Tools 3235 Ramp-Type Spark Plug GapperEditor’s Choice1 x 1 x 1 inches (2.54 cm)0.8 ounces (ca. 30 g)0.02 to 0.1-InchesFlexibility and convenience. This option is very easy to use since it has a very clear scale. Made entirely of steel, which ensures reliability. In addition, this option is very cheap.
A & E Hand Tools 4450A
Solid Choice7.7 x 3.4 x 0.5 inches (1.27 cm)0.8 ounces (ca. 30 g)0,20 inch to 0,80 inch It has a convenient measurement scale. Thanks to the handle it can be used in various situations. It is suitable for various models of automobiles since it has a wide range for measurements. Has a pocket-clip.
CTA Tools 3238 9 Wire Spark Plug Gap Gauge

Best Value2.2 x 2.8 x 6 inches (ca. 15 cm) 1.44 ounces (ca. 54 g).0.025-0.55 -inches.Steel construction ensures quality and durability.


What does a spark plug do?

They create a spark that starts your car’s engine.

Can an engine run without it?

No, a car will not go without well-functioning spark plugs.

What happens if I don’t gap my spark plugs?

Large or small clearance between the spark plugs is dangerous for the car. A small gap may cause the engine to ignite. A large gap can cause the ignition to not work at all.

Is this device suitable for all cars?

Most cars have the same spark plugs with a similar factory clearance. Therefore, such a device is suitable for almost everyone. Old models are slightly different from new ones, so if you do not have a new car model, pay attention to this

How do I know if the gap needs readjusting?

You must know the correct clearance between the spark plugs in your car. The device that you will be measuring should be with these settings. Insert the device between the spark plugs and check the distance. If it fits perfectly, then nothing needs to be changed.

Do I have to replace device for measuring distance every time I replace my spark plug?

It is best to purchase a new device for measuring since the old one may wear out.

Our best choice

Our best choice is A & E Hand Tools 4450A. This is an easy-to-use device for measuring the space between spark plugs. It has a convenient and clear measurement scale. In addition, it has a pocket-clip that makes it even more convenient to use. Also it has a recess and with such recess, the electrodes can be easily adjusted.

The clearance between spark plugs is very important for the proper operation of the vehicle and correct performance. It must be regularly measured and adjusted. For this, each motorist should have a device for measuring the distance between the spark plugs. The choice of such a device must be taken seriously and with a decent background.