What Is M10 Bolt Size? [Dimensions Chart]

Bolts are used worldwide and have played a major role in the industrial revolution. They are among the few tools which are still used in mostly the same form as they used to be before.

There isn’t an industry where they aren’t used.  As new products are coming out, the old ones are being updated to make them more efficient.

Products are taking over the market from the smallest things to the largest because they’re more cost-effective, generally easy to use, and have improved functionality.

High strength, high tensile strength bolts are superior to their counterparts because they can handle greater fatigue and have better bearing capabilities. 

They also have a better design and are more likely to be used as they offer greater load-bearing capacity.

These high-strength friction grip bolts are versatile and can be used in large buildings, machinery, and even steel projects!

Iron and steel is a high-strength material used in various applications, from construction to manufacturing. They are commonly used in bolts and screws with grooves on their surface to enhance friction.

In this article, We will talk about M10 Bolts.

Let’s get started!

What is an M10 Bolt?

What Is M10 Bolt Size


Metric fastener sizing is calculated by diameter, pitch, and length. Nuts are measured in millimeters. If the angle isn’t specified, the nut is assumed to be a coarse thread by default.

Here is an example of how metric sizing:

M10-1.0 x 20

Taking a closer look at this description, let’s explore its meaning:

  • M = This designates the fastener as a metric size
  • 10 = The nominal diameter in millimeters
  • 0 = The thread pitch, or distance between threads, in millimeters
  • 20 = The fastener’s length, in millimeters
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For example, a coarse thread fastener would be labeled with the following text: If the size of your fastener is listed as M10 x 25 and no thread pitch is listed, it’s assumed to have a coarse thread.

The 25 indicates its length, and a matching nut would be labeled M10.

Metric Standard Bolts and Sizes

This chart is only to help find the nearest equivalent-sized fastener. Due to the differences in thread angles and pitches, the thread sizes shown are not directly interchangeable.

Metric fasteners are often referenced using ‘M’ sizes, for example, M3, M8, M12.

But the size of a metric fastener is more accurately specified using the diameter, pitch, and length dimensions, in millimeters. For nuts, the size dimensions used are simply diameter and pitch.

Metric fasteners are classified by thread pitch and can be either coarse or fine.

Compared to standard “inch” fasteners (commonly used in North America), coarse metric fasteners tend to be less rough, and their threads are more closely spaced—for a comparable size.

Fine metric fasteners can be more or less fine, depending on size.

Watch this video for further help on measuring bolts: Measuring Metric Bolts

YouTube video

M10 Bolt Standards

M10 bolts are ideal for a range of applications, from construction to home. A hexagonal head and a threaded stem can be used with either a nut or tapered hole.

They’re strong and adaptable, so whether your project is big or small, you’ll need these reliable bolts!

M10 Bolt Clearance and Tapping Hole

Metric bolts are made to have a shank diameter of typically 15.97mm.

This means that a 16mm bolt will fit through a 16mm hole, but it’s common practice to drill holes slightly larger so that misalignment between parts doesn’t happen.

These are known as clearance holes.

Standard Spanner and Allen Key Sizes

The correct spanner and Allen Key sizes are given in the table above for the normal bolt and nut sizes found in many different types of machinery.

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It is important to use ring spanners (or the ring end of a combination spanner) to help minimize any chance of slipping.

M10 Bolt Maximum Torque Thresholds

M10 Bolt Maximum Torque Thresholds

Torque is defined as the measure of the amount of force that an object can exert about an axis or pivot point. Levers use this principle, and you probably remember the see-saw on the playground.

You were able to spend countless hours going up and down on them with your friends because of the phenomenon of torque.

The maximum recommended bolt torque thresholds are in the table above, assuming that the threads are lightly oiled.

Doing a bolt up to the specified torque should set the tension in the bolt to approximately 85% of the proof load given in the table.

If your machine manufacturer has provided torque settings, do not use the settings given in this table.

Make sure you use a torque wrench to apply torque to fasteners and prevent bolt heads from snapping off. Whether manufacturing a product or maintaining one, the proper torque should always be used.

M10 Standard Proof Loads

Here you can find the standard proof load of a bolt in Newtons, also known as the absolute maximum load that a bolt should be asked to carry.

In practice, manufacturers will design their machinery so that the bolts hold a lot less than this for a good safety factor to the design.

M10 Bolt Size In Inches

This table compares various metric sizes to the closest inch equivalent…

Likewise, people ask, are m10 and 3/8 the same?

Since 10 mm is bigger than 3/8“, the simple answer is, “NO”. But you CAN drill the hole out to either 25/64″ (for 3/8-24) or the letter “X” (. 397″)( for 3/8-16), and tap for a Helicoil.

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Subsequently, the question is, is m10 the same as 10mm? The M8 will measure about 8 mm in diameter, more likely, just a touch undersize, (. 31496″) The M10, about 10 mm in diameter, (. 3937″) and the M12 about 12 mm in diameter, (. In this example the bolt is 10 mm in diameter, 40 mm long, and the threads are 1.25 mm apart.

M10 Standard Thread Pitches

The type of threading is one of the most important decisions you will make when creating a project. It can help determine how easy or hard your task will be to complete, the cost, and the quality of your final product.

Metric Coarse

Coarse thread fasteners are a great choice for most applications because they have a little extra tolerance in threading.

They often get picked for construction projects because of their ability to be damaged and still work effectively.


  • Durable and less likely to be damaged
  • Tap better into brittle materials
  • Less likely to cross-thread


  • Due to long thread depth, it may not be applied to thin walls

Metric Fine and Extra Fine

Fine threading is a type of thread with a very shallow pitch and peaks and valleys that are much shallower than coarse. As a result, fine threading can be easier to tap and use for smaller threads.

But, fine threading also provides less resistance to vibrations, making it ideal for environments where vibrations are an issue.


  • Shorter thread depth allows application in thin walls
  • Stronger in both tension and shear
  • Greater adjustment accuracy because of their small helix angle


  • More susceptible to thread galling
  • It tends to loosen under vibration
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Frequently Asked Questions (FAQs):

What Is M10 Equivalent To?

M10 bolts may be equivalent to 3/8, they might be very close, but there are still differences. Yeah, they’re close, but the 3/8″ bolt is about 0.019″ smaller, and the pitch is very tight, so the 3/8-16 bolt will thread in the 10mm x 1.5, but the 10 x 1.5 bolt will not fit the ⅜.

How Strong Is A M10 Bolt?

Steel bolts are graded according to newtons per millimeter squared for bolt tensile strength compared to yield power. For example, a steel bolt with a rating of 5.5 will provide roughly 500 newtons/mm2 of bolt tensile strength and approximately 400 newtons/mm2 of yield strength.

Why Is Torquing a Bolt Important?

Why is proper torque on a bolt or nut important? If you’ve ever experienced a broken driveshaft, you might have to consider it. Proper torque helps to prevent things from going haywire while you’re on the road.

When torque is not correctly applied to the bolts and nuts, they can wear out quickly and cause failure. Because each application is different, this can result in a costly decision or even death.

When should I use fine thread nuts/bolts?

You’ll need a fine threaded bolt when working with metal. For example, if you have a metal piece that’s already threaded onto another piece of metal, you’ll need a fine threaded bolt to affix them together.

Fine threaded nuts and bolts work best with pre-threaded metal parts. Fine threaded nuts and bolts are great for applications that need finer adjustments, are exposed to many vibrations, and require less torque to tighten.

And all you need to know about coarse threaded fasteners is that they are resistant to stripping, less likely to nick, and are easier and faster to assemble.

What is the difference between the grades in Metric and Imperial bolts?

Metric bolts are measured in millimeters, while Imperial bolts are measured in inches or fractions of inches. The main difference between the grades is how each is measured, but there are other differences!

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Metric bolts are designed to utilize the metric measurement system, even if they are made in the United States. Metric bolts have markings on their heads that indicate their tensile strength.

Standard-sized fasteners are primarily made in the United States. The two types of standard bolts are found in the Unified National fine thread and coarse thread.

You will not usually find numeric markings on the heads. Instead, you will see lines on the heads. To discover the strength of an imperial bolt, you have to measure the number of threads.

Bolt Grade Explained

YouTube video


When you find yourself working on a project, and you come across M10 bolts. Be sure to visit this article to use as a guide or a manual to assist you.

This article covers the M10 bolts and their specifications. Every detail you need to know about it is here, so keep this article close to you!

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