Angle Grinder Sizes – What’s The Right Size for You?

When you need to use a power tool for a certain project, one of the most important things to do is choose the correct tool and the right size for the application at hand. If the tool is too small, chances are it won’t have the necessary amount of power to perform well; on top of that, it might require way too much time to get the job done. On the other hand, a tool too big might damage the material you are working with. What about angle grinder sizes then? What’s the right size for you?

When talking about angle grinder sizes, we are referring to the cutting disc size, ie its diameter. The most common sizes available are the following:

  • 4″ – 100mm
  • 4½” – 115mm
  • 5″ – 125mm
  • 6″ – 150mm
  • 7″ – 180mm
  • 9″ – 230mm

What size angle grinder do you need then? It depends on many things. The driving factor is the activity you want to use it for. For heavy cutting, for example when working with thick metal, the bigger the better. If you need to be more precise, then a smaller angle grinder might be the best for you. We’ll get more into details in the article.

First, we’ll go through each of the aforementioned sizes, discussing their specs. Then, we’ll decide what’s the right angle grinder size for you: we’ll go through a series of common activities and determine which is the right size for them.

Angle Grinder Sizes – Full Guide

“Let the Sparks Fly – Makita 9557NB Angle Grinder” by toolstop is licensed under CC BY 2.0

As a starter, let’s discuss the most common angle grinder characteristics. There are many things to keep into consideration:

  • Wheel diameter: As mentioned before, the most common sizes start at 4 inches, going up to 9″. When going up in size, power will also increase, while speed diminishes. Always keep that in mind.
  • Power: this factor determines the cutting capacity of the tool. Harder materials, extensive jobs require more power. It also influences all the other characteristics: a more powerful angle grinder will also be heavier and slower. More torque means less RPM. You’ll have to compromise between the two. Power output usually starts at around 700 Watts with 4″ grinders, going up to 2500 W with bigger models.
  • Speed: this characteristic is very important for jobs like sanding/grinding. Higher speed also guarantees cleaner cuts. Smaller grinders have higher speed, around 11,000 RPM; bigger models go as low as 6,000 RPM.
  • Weight: obviously, a bigger grinder requires a heavier apparatus to keep it going without problems. If you are going to use this tool extensively, you want to keep this factor in mind. Try getting the smallest grinder you can afford for your application. Let’s throw some numbers: smaller grinders start as low as 4 lbs, up to around 20 pounds for 9-inch angle grinders.

Now, let’s talk about each angle grinder size, discussing their characteristics and best applications.

4 Inch Angle Grinder

This is the smallest angle grinder you can get. To get an idea of the specs of this size of angle grinders, let’s take as an example the Makita GA4030K 4″ Angle Grinder. It comes with a small 6 AMP motor. Considering that it needs a voltage of 120 Volts, it means that it develops 720 Watt of power. What about its speed then? The motor delivers 11,000 RPM in no-load conditions. Finally, it weighs at 3,7 lbs, which is probably the lightest an angle grinder can get.

What about its applications? Its size and portability make it ideal for cutting thin metal and grinding.

4-1/2 Inch Angle Grinder

The specs of these angle grinders are pretty much the same as the earlier category. Motors deliver around 11,000 RPM, developing about 700 Watts at 120 Volts. At this size, the most common angle grinder you will see is the Bosch 1375A.

Applications are similar to the 4-inch angle grinder. These small guys perform best with small jobs around the workshop. They are ideal for a hobbyist that doesn’t need to perform extensive cuts on thick metal.

5 Inch Angle Grinder

Let’s go up in size a bit with the 5 Inch model. Angle grinders in this category have more powerful motors, ranging between 9 AMP and 12 AMP, meaning they deliver between 1080 and 1440 Watts at 120 Volts. Bigger motors mean heavier tools: with these grinders, we are at around 7 pounds.

Let’s talk applications for a moment. Considering its specs, this angle grinder doesn’t go that far from the earlier models: although, the additional power might suit contractors that need a compact, yet powerful tool. It’s also a good choice if you are a DIYer looking for a small tool, but a bit more powerful than the aforementioned models.

6 Inch Angle Grinder

It’s time to move into the middle-sized angle grinders. When compared to the 5-inch angle grinder, the main difference is the additional power output: we are in the 10 to 13 AMP range here. Weight is similar; speed is a little lower, around 9,000-10,000 RPM, which is expected when going up in size.

This angle grinder dimension is quite uncommon. Generally, you either get a 7-inch model, or a smaller one. In my opinion, you should choose this size if you want a powerful yet not-so-big tool that can get you faster results when compared to smaller models.

7 Inch Angle Grinder

die grinder vs angle grinderThis is one of the most popular size angle grinders with the 4-1/2 inch model. It comes with a powerful motor, ranging between 13 to 15 AMP depending on the model. The power output consequently ranges between 1600 to 1800 Watts at 120 Volts. When it comes to speed, these grinders deliver between 6,500 to 8,000 RPM on average. Weight goes up significantly in this category. We are talking 15 to 20 pounds.

What about the applications? Let’s start by saying that this angle grinder is the best compromise between size and power. That’s why this model is so popular among a wide range of professionals, going from metal operators to construction workers. It can cut through a wide range of materials, from different types of metals to concrete or stone. It can also be used for extensive grinding activities.

9 Inch Angle Grinder

Finally, let’s spend two words about this big boy. Specs are quite similar to the 7-inch angle grinder we talked about earlier: around 15 AMP motor with a delivered speed close to 6,500 RPM. Some of these models need a 230 Volts supply due to their large motors. Keep that in mind.

This model is commonly chosen by folks that need an angle grinder that can withstand heavy usage. We are talking about contractors, welders, construction workers, and so on. It can deal with the hardest stones and thickest metals.

What’s the Right Angle Grinder Size for You?

As you can see, there’s a wide variety of angle grinders sizes you can choose from. It can be quite confusing at first. Don’t worry though. As a matter of fact, the 4-1/2 and the 7 inches sizes cover 99% of your needs. On top of that, it’s all a matter of considering the applications you will use the tool for. Here are some suggestions that might help clear your mind:

  • For small jobs around the house, get a 4-1/2 inch angle grinder. The Bosch 1375A is a no brainer. You’ll use it for cutting various materials such as metal and concrete, and grinding. It’s also a good addition to your tool’s arsenal if you are a professional, in case you ever happen to need a compact cutting tool.
  • If you need some more power, for example in the case of extensive home restoration projects, get yourself a 7-inch angle grinder such as the Dewalt DW840. It’s also a common choice between general contractors, people in the construction business, and so on.
  • Finally, if you are a professional that needs a heavy-duty tool for extensive cutting and grinding, consider buying a 9-inch angle grinder.

FAQ [Frequently Asked Questions]

Here are some of the most common questions when it comes to angle grinder sizes. Let me know if you have any more in the comments below!

What Size Angle Grinder to Cut Paving Slabs?

If you need to cut through paving slabs, you need to consider a couple of things before choosing the correct angle grinder size for the job. Which are the extension of the cut, thickness, material.

If you need to cut a small portion of a slab, then you should be fine using a small angle grinder, such as a 4-1/2 inch model. On the other hand, for extensive projects, it might be better to get a bigger angle grinder, or else it will take you forever to cut through slabs with a smaller one.

As I said before, also consider the paving slab thickness. For thin slabs, let’s say up to 10-15mm, you could try using your small grinder. Many slabs are way thicker than that, though. Some might be up to 70 mm thick. That will require a bigger and more powerful tool, such as a 7-inch.

Don’t forget to consider the material hardness. Harder materials require more power to get through them: keep that in mind.

Finally, make sure to use the appropriate cutting wheel; a diamond blade will cover most of the applications.

What Size Angle Grinder to Cut Bricks?

To choose the correct angle grinder size to cut bricks, the key thing to consider is the material thickness. Make sure to choose a size that can cut all the way through the bricks. A 4-1/2 inch angle grinder should be sufficient in most cases. At this point, you might ask yourself if a small angle grinder like that is powerful enough for this type of application. In my experience, I’d say yes. Bricks are not as tough to cut as concrete, for example. If the size is sufficient, don’t worry about the power, it will be enough.

What’s the best blade for this type of application? Again, a diamond blade is ideal. It guarantees clean cuts and will wear way less than other common cutting wheels.

Finally, don’t forget to wear a dust mask when cutting bricks. You will produce a huge amount of debris when cutting this stuff, make sure to protect yourself properly.

What’s the Most Common Angle Grinder Size?

As we said before, the most popular angle grinder between the small ones is the 4-1/2 inch model, while the 7 inch dominates the medium to heavy category. This is because they are the most versatile grinders available at their size, putting together power and compactness. And to be fair they are also the only size available in most hardware stores.

Then, the following question might be: what’s the most common size between the 4-1/2 and the 7 inch? I would say the smallest one is the most popular. This is due to its many applications amongst DIYers, from cutting various materials to grinding and sanding. The 7 inch is not as common if you consider that its use is limited to heavier jobs.

What’s the Best Angle Grinder Size? And What’s The Biggest?

As mentioned earlier, there’s no definitive answer to this question. The best angle grinder size is related to the application at hand. So if you need to perform random jobs around the house, in your case the best angle grinder size would be a 4-1/2 inch or something like that. A compact yet powerful tool.

On the other hand, if your application is heavier and you need more power, then a bigger angle grinder such as a 7-inch model is probably better for you. If you are a professional and you need even more power, then get a 9-inch model, which is also the biggest angle grinder size available. They are perfect for extensive use and abuse, day in and day out.

4.5 vs 7 Inch Angle Grinder

This is one of the most asked questions since these are the most common sizes available. In short, get a 4.5-inch angle grinder if you need a versatile tool for cutting, grinding, sanding, etc. It’s the perfect size for most of the jobs a DIYer needs an angle grinder for. In case you have to perform heavier jobs, like a professional would, it’s better to get a bigger and more powerful angle grinder like the 7-inch.

4.5 vs 5 Inch Angle Grinder

angle grinder with diamond blade
Hustvedt, CC BY-SA 3.0 <>, via Wikimedia Commons

What’s the best angle grinder between a 4-1/2 inch and a 5 inch? Well, there isn’t much of a difference between these two. The only relevant difference is in power: usually, 5-inch grinders are equipped with slightly bigger motors which also add to the tool weight when compared to smaller models.

Besides that, the 4.5 and the 5-inch are basically equivalent.

Final Thoughts

So there you have it, a complete review of all angle grinder sizes available on the market, starting from the smallest (4-1/2 inch) to the heaviest (9 inches). In addition to the disc dimension, there’s a significant increase in power and weight when going up in size, at the expense of the maximum rotational speed. This makes bigger angle grinders suited for heavier applications such as cutting thick metal, extensive masonry work, etc.

If you are a hobbyist, make sure to evaluate carefully the type of activities you are going to use the angle grinder for. Based on that, you’ll be able to choose the correct angle grinder size for you without problems.

Finally, a couple of words about safety precautions are due. Whether you are going to operate a small or big angle grinder, remember to always put your security in the first place. Wear eyes and ears protection. A face mask or a respirator is also suggested, especially when working on stuff that develops a lot of dust such as concrete, tile, masonry, etc.

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