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Angle Grinder Sizes | Which is the Right Size for You?

If you are into automobiles, metalworking, or construction business, then you might be familiar with Angle Grinders. They are one of the popular power tools. Angle Grinders are also known as Side Grinders or Disc Grinders. Like other similar power tools, even Angle Grinders come in different sizes. For small and precise cutting, small size is suitable. But for general purpose cutting and grinding, a large size disc is a better choice. What are some popular Angle Grinder Sizes? Which is the right size for you?

In this guide, we will take a look at Angle Grinders. First, we will tackle the basics. Then, we move on to different Angle Grinder Sizes. After that, we will find out the right angle grinder size for the job.

What is an Angle Grinder?

An Angle Grinder is a power tool that grinds steel, wood, or material at a right angle. The motor rotates an abrasive disc at a very high speed, usually between 3,000 to 12,000 RPM.


With this high-speed turning disc, you can grind or cut wood, masonry, and metal. Here are some of the things you can do with an Angle Grinder:

  • Chop off extra prices of metal
  • Sanding and other finishing (low RPM)
  • Remove old paint and rust
  • During emergency rescue missions

All angle grinders come with a safety guard. This will protect you from flying shrapnel if the disc breaks while operating at thousands of RPM. It will also protect your hands while using the angle grinder.

SAFETY WARNING: Do not use the angle grinder without the safety guard.

The disc attaches to the main grinder unit with the help of a flange and nut. The design of this nut is special as it recesses into the center of the wheel.

When you purchase the tool, you will get a special wrench in the package to tighten or loosen the nut of the disc. Keep this wrench somewhere safe.

Types of Angle Grinders

There are three basic types of angle grinders. They are:

  • Corded Electric
  • Cordless Electric
  • Pneumatic (Compressed Air)

It is very rare but you can also find gas-powered angle grinders. As you can see from the names, the first two types have electric motors while the third one has a pneumatic engine.

Corded Electric Angle Grinders are a popular choice for most metalworking jobs. Simply plug in the power cord to an outlet and start using the tool. These power tools are also inexpensive of the three while also being light in weight.

Cordless Angle Grinders are gradually replacing the corded options. Apart from portability, these tools also offer great performance. Due to the battery, the weight of cordless angle grinders is more. Cost is also more than corded counterparts.

Brands like Makita, DEWALT, etc. allow you to use one style of battery with several similar power tools. This might reduce the cost in the long run with multiple tools.

The pneumatic Angle Grinder runs on compressed air. Automobile garages and workshops with several pneumatic wrenches and other compressed air tools will have an angle grinder in their chest.

Angle Grinder Sizes

The size of the angle grinder depends on the job you are working on. When we say angle grinder sizes, we actually mean the diameter of the cutting/abrasive disc.

Apart from cutting discs, you can also use sanding discs and wire wheels with an angle grinder. But make sure that the tool has an adjustable speed as sanding usually requires a low RPM (between 600 and 1000).

Coming to the angle grinder sizes, they are usually available in the range of 4” to 9”, which is about 101.6 mm to 228.6 mm. In this, the 4-1/2” and the 7” angle grinders are extremely popular.

The following list shows the common angle grinder sizes with dimensions in both metric as well as imperial. Note that these dimensions are the diameters of new grinding discs.

4” 101.6 mm
4-1/2” 114.3 mm
5” 127 mm
6” 152.4 mm
7” 177.8 mm
9” 228.6 mm

Small angle grinders will have higher RPM. For instance, the 4” Angle Grinder from Makita has a no-load speed of 11,000 RPM. They are also very lightweight at 3.7 lbs. to 4 lbs.

The 4” Angle grinders are not as common as the next size i.e., a 4-1/2” is a better option. Speaking of 4-1/2” discs, they are some of the popular angle grinder sizes in the current market.

Just like the 4” options, the 4-1/2” Angle Grinder is also lightweight, at around 4 lbs. to 5.5 lbs. This additional weight is a result of a more powerful motor.

Most 4” Angle grinders have a 6 amp or 7 amp motor. But the 4-1/2” Angle Grinders have an 11 amp or 13 amp motor.

As we move higher in angle grinder sizes, the rotational speed of the disc becomes less. A 5” Angle grinder has a speed up to 10,000 RPM, while a 6” one has a speed between 9,000 RPM to 10,000 RPM.

The 7” angle grinder is another popular size in the “larger” angle grinder category. They have a powerful 13 amp or 15 amp motor and rotate the disc between 6,500 RPM to 8,000 RPM.

What is a Right Angle Grinder Size for You?

Small Angle Grinder sizes i.e., with discs less than or equal to 4-1/2” are suitable for a wide range of cutting and grinding jobs.

You can work on metal as well as masonry with these size tools. You can also work in tight spaces due to their small and compact sizes.

The 7” angle grinder is a medium size while we can consider the 9” and above as a large angle grinder. If you work with a lot of metals, be it aluminum, steel, bronze, iron, and even bricks and concrete, then the 7” angle grinder is an obvious choice.

It has a powerful motor that can deliver excellent performance for demanding and tough jobs.

We recommend you to have a good quality 4-1/2” Angle Grinder as well as a 7” Angle Grinder in your garage or workshop. The smaller one can serve you well for cutting and grinding. While the larger 7” one is suitable for general purpose jobs, including sanding.


Angle Grinders are very popular power tools. We use them in construction, automobiles as well as regular metal working. There are several angle grinder sizes but the 4-1/2” and the 7” options are very common and popular.

In this guide, we saw the basics of angle grinders along with some popular disc sizes. We then saw a brief note on the suitable angle grinder size for a job.

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