Angle Grinder Sizes. How to Choose the Right Size?

The angle grinder, which is one of the most useful power tools comes in different sizes. It has a wide variety of applications, mainly because of its efficiency and flexibility of use.
Angle Grinder Sizes
With a multitude of applications possible, the size of angle grinders will also vary to better suit differing projects. The following guide will explain the most common angle grinder sizes available and how they are effectively put to use.

What Size Angle Grinder Do I Need?

How you choose the size of your angle grinder depends upon the characteristics of the project at hand as well as your own personal requirements. In general, angle grinders of the smaller size range (below 6-inches) are better suited for projects that require precision while the larger models, 6-inches and above, are excellent for larger projects where heavy usage will be inevitable.

How the Size of an Angle Grinder is Measured?

The size of an angle grinder is measured by the diameter of the disc that is mounted onto the grinder. You also need to consider the power of the motor of the tool when evaluating an angle grinder’s capabilities.

Size of an Angle Grinder This dimension also indicates the maximum disc diameter you can mount on the tool.

Generally, these two factors will correspond with each other. This can be observed easily as when a larger angle grinder disc is used, a more powerful motor is required to support the disc. In simpler terms: the bigger the disc = the more powerful the motor required vs the smaller the disc = the lower the amount of power output required.
Disc width (diameter) is measured in inches and/or in millimeters, while the motor size is measured in terms of watts or horsepower. These terms will always depend upon the model and the location of manufacturing.

Angle Grinder Size Chart

Following are the different sizes of angle grinders in inches and millimeters and their approximate motor power in watts.

Size in Inch Disc in Millimeters Approx. Motor Power
4.5 inch 115mm 700 –  1300 watts
5-inch 125mm 1200 – 1500 Watts
6-inch 150mm 1400  –  1600 Watts
7-inch 180mm 1200 –  2400 watts
9-inch 230mm 1600 – 2600 watts

What Is the Most Popular Size Angle Grinder?

The 4.5-inches angle grinder is the most commonly used size. This site is easy to control, inexpensive, and offers better portability and handling.

Common Angle Grinder Sizes & Their Uses

The best way to find the right-sized tool for your job is to consider the various uses of your angle grinder that you perform most often. Following are some of the most common sizes and the tasks they are suitable for.

4 ½ inch Angle Grinder

The smallest model on this list, the 4.5-inch angle grinder is excellent for when working upon light-duty projects where tasks could include light grinding, sanding, cutting metal, polishing, deburring of thin/soft materials such as sheet metal, tiles, or wood.

The advantage of this compact model size is that it is extremely safe to use (the risk of grinder kickback is minimal) and proves to be perfect for beginner operators who are just beginning to learn how to handle a grinder. The 4 ½ inch grinder is also an excellent tool for DIY, repair, and general home use.

5-inch Grinder

Similar to the 4½ inch with its capabilities, but with a larger disc capacity and motor.

The 5-inch grinder can accommodate ½ inch extra of disc surface area and houses a slightly more powerful motor (with higher RPMs). This allows for the more rapid completion of tasks and for a slighter wider range of capabilities when working upon heavier materials.

All of these while still offering good control and energy efficiency.

6-inch Angle Grinder

The 6-inch grinder is excellent for working upon small-medium sized materials of different hardnesses and proves to be very durable as machines.

The biggest advantage of the 6-inch grinder is its versatility; it can be used in small spaces and to great effect, for precision work as well as for heavier projects that require an extra boost of power. Industrial professionals use this grinder more so than DIYers.

This angle grinder size is perfect for a range of jobs including metalworking, brick cutting, woodworking, tile cutting, and more.

7-inch Grinder

This is a relatively larger sized grinder that sits within the medium to large size range.

7-inch grinders are great as an all-round machine for heavy-duty or large-scale projects and are predominately used for working on concrete and metal. Compared to the small angle grinder sizes, the 7-inch houses a much larger motor and disc surface area, making it excellent for use upon projects where speed and durability are important while still maintaining a degree of controlled handling.

9-inch Angle Grinder

This grinder is massive in size and particularly dangerous when handled without experience. Despite this, the 9-inch grinder is by far the most productive when considering time efficiency and durability. It is great for all large-scale grinding works (eg: cutting thick steel or sanding large surface areas).

However, due to its exceptionally large size, this power tool is difficult to control and is not suitable for precision jobs.

According to Tasks

As we have already mentioned, the size that you need will completely depend upon the task at hand.

What Size Angle Grinder to Cut Bricks?

To cut bricks the larger models such as the 7 – 9 inch grinder are much more efficient. The large size discs will not only allow you to cut the bricks in a single pass but also works best for heavier workloads than the smaller models. Therefore, it makes sense to use a larger model as such for larger projects and vice versa with smaller models.

Angle Grinder Cutting brick

This means that if repeatedly cutting a multitude of bricks on a production line, a bigger grinder size is better for an operator’s overall efficiency.

Cutting Paving Stones

You will need a large 9-inch angle grinder to cut pavers. But I strongly recommend you consider a masonry saw to cut paving stones, concrete, etc. If you do not want to invest in a dedicated tool, you could use an angle grinder with a diamond wheel.

Angle Grinder cutting paving stones

You can find more information on cutting concrete with an angle grinder here.

What Size Grinder for Welding Works?

The angle grinders of the smaller size range will prove to be more precise as well as allow for excellent handling. This is an attribute that would be great for unusual cut shapes or when working upon delicate sheet metals.

I recommend getting a 4.5-inch or 5-inch grinder with flap discs for weld cleanup jobs. You may need a larger size tool if you have to cut thick metal sections. Refer to the guide on angle grinders for welding for more details.

Understanding which angle grinder size would better suit your project is important and comes down to understanding the individual pros and cons of using a specific grinder size over another and also, visualizing accurately what your project requires.