What Size Are Battery Terminal Bolts?

Battery terminal bolts are a type of bolt used to hold the battery in place.

This type of bolt is typically found in cars and is very different than other types of bolts. For example, the head is not flat but rather pointed, and the length can range from 3/8 an inch to 1-inch long.

There are many different sizes for car batteries, so it’s important that you get one that will fit your specific needs. If you’re unsure what battery terminal bolt size your battery needs or how to change it yourself, consult with a professional like those at Your Mechanic!

What are battery terminal bolts, and why do they matter?

Battery bolts can also be referred to as terminal nuts. The purpose of the bolt is to hold your battery in place. These bolts are placed on cars and serve a slightly different role than other items, such as holding metal together. To start off, you will notice that the head of this type of bolt is not flat. Instead, it is pointed and can be anywhere from 3/8 inches to one inch long.

The importance of this bolt is to make sure the battery does not move or fall out while driving. This type of nut can be purchased at an auto parts store and is usually only about two dollars per nut. These bolts are so inexpensive because one size fits all, and they do not need to be custom-made for each different car, making them less expensive to produce. They can also be bought in different quantities for those who are constantly working on vehicles.

This type of bolt is made out of copper and zinc, which is a common metals combination used in current-day car parts. This material will not corrode or rust while sitting outside in the elements when compared to other types of bolts. The bolt has a non-conductive surface. This is because it does not have to interact with the electricity in your car, so it would not make sense for this part of the bolt to conduct.

People typically use these when replacing their battery and do not want any issues occurring, such as by having a loose-fitting battery that will move around or not be in place and cause damages to your electrical system.

For example, if you had a loose battery that was not secure, it could come to lose when putting the car into gear while driving and touch different wires connected to your radio. When many wires are touching at once, the current will flow; this causes issues within the electrical system. Not only will you have to replace your radio, but the car may not start or shift gears properly.

Some people try to find other options such as cable ties or tape in place of battery bolts for a temporary fix. This is a much riskier approach since it can cause dangerous issues with the electrical system. If you are going to be working on your car a lot, it would be smart to get some spare battery terminal bolts so that you can change them when they start to rust or corrode.

How many bolts is a car battery and how to determine what size bolt is on a car battery?

The size of the bolt on your battery is not something you want to mess up. If you try to replace it with the wrong size bolt, it won’t work.

You can determine the size by following these steps:

1) Determine if you have a side post or top post battery. Side posts are more common in automotive applications like cars and motorcycles, but top posts are more common in industrial applications like forklifts, cranes, and other heavy-duty vehicles.

2) Look at the length of your bolt head. The length ranges from 3/8-inches to 1-inch, which is longer than standard bolts, which vary from 1/4-inch to 1/2-inch.

3) Look at the size of your bolt shaft. Standard sizes range from 3/8-inch to 1/2-inches in diameter.

4) Compare your bolt length and shaft size with the table below to determine what you actually have. Example: A bolt is 1.25 inches long (between 1″ and 1.5″) but has a diameter of 0.625 inches. First, the bolt is longer than 1-inch (greater than 1.5″), which could be a top post battery. Second, it has an inch diameter that falls between 0.625 inches and 0.750 inches, indicating that you have a 3/8-inch to 7/16th inch bolt size.

Finding a replacement for your car’s battery bolt

It is crucial to find a replacement for your car’s battery bolt if it breaks, especially if you cannot find the original bolt. The bolts vary by size and type of application.

Firstly, you will need to identify the type of bolt used on your battery. This might require you to contact the manufacturer or other mechanics who work on your car to find out what type of bolt you should use. If you do not have any luck with these details, there are typically spare parts located at hardware stores and auto supply stores that offer durable substitutes as well. You can also order new bolts online from companies like McMaster-Carr and Grainger.

Tips on how to install a new battery bolt

The best way to install one of these bolts is to:

-Remove the old bolt and make sure that it will not fall into an unreachable area.

-Lubricate the bolt threads with petroleum jelly or other form of lubricant to ensure that the new bolt goes on smoothly.

-Place the new bolt in and pull up with as much force as possible. Check if the bolt is straight in by making sure that both ends are flush against the surface and there are no gaps between the threads and surface. If the bolt is crooked, then something may have been wrong with it, and replacements need to be obtained.

-Tighten the bolt using a socket or wrench.

It is of utmost importance that you do not over tighten these bolts as this can damage the battery and cause more serious problems in the near future, if not immediately.


Bolt sizes are a critical consideration when replacing your battery or for any other automotive work. To determine the size of your bolt, you’ll need to know if it is a side post or top post and then measure its length and diameter. If you’re unable to find the original bolt at an auto supply store, hardware store, or online retailer like McMaster-Carr, be sure to take measurements before ordering new bolts so that they can be delivered in time. Remember not to over-tighten these bolts as this will damage them!

About the author, Phil Borges

Phil Borges is a battery aficionado. He's written extensively about batteries, and he loves nothing more than discussing the latest innovations in the industry. He has a deep understanding of how batteries work, and he's always on the lookout for new ways to improve their performance.