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Angle Grinder Size

Angle Grinder Size Should Be Right For Your Job

Choosing the angle grinder size can be tricky if you are not yet familiar with these handy tools. As they come in different sizes, power, capacities, and usage you have to know which will fit your kind of work. 

Regardless you are a DIY guy who owns a welding machine or running a large metal construction business, you must know which kind of angle grinder you must have. 

Here are the different sizes of angle grinders that you can buy in today’s market: 

4½ inch – 115mm  / 5 inch – 125mm / 6 inch – 150mm / 7 inch – 180mm / 9 inch – 230mm

All of these are essential tools. However, not all of them would fit every individual’s needs. For example, if you have a home workshop you may prefer the most popular 4.5-inch because of its lightweight and sleek size. 

But if you are involved in professional work such as masonry, metal construction, and fabrication industries the 4.5-inch would be too small for your convenience thus you may prefer the 7 or 9-inch size. With their powerful motors and larger disc capacity, they can do larger work in quicker time compared to their smaller counterparts.

How Wattage Influence the Capacity of the Angle Grinder

If you are looking for a grinder either for your home workshop or for your metal fabrication business, then you must know the capacity of the unit first before buying it.   

The power of an angle grinder is not only based on how fast its disc can spin but also on the capacity of its motor. For example, a 4.5-inch grinder may have 10000 rpm which makes it a perfect grinding companion for small metal grinding work.

However , the 9-inch grinder can run at only 6,000 rpm but can still do much work on a larger scale. 

How does this happen?

Because the 9-inch grinder has a bigger and more powerful motor and a larger disc capacity so it can finish more workfaster. Obviously, the bigger the motor, the bigger the grinder and the more work you can finish with it. 

However, because the 9-inch would be too big for small grinding work, a DIYer would still prefer the 4.5-inch angle grinder.

welding bevel

Angle grinders also need the power to run. The small units require less power though their discs spin faster while the larger units require more power. This power is expressed in wattage or watts.  

Knowing the angle grinder wattage is very important because it enables you to identify how much energy the grinder needs for the tool to run its motor efficiently. 

Furthermore, if you want to know how powerful the motor of the grinder is, check the angle grinder watts indicated on the unit. 

Remember that for every 746 watts this equals 1 horsepower (hp). So to get the horsepower of a grinder you have to divide its watts into 746 watts. For example, a 1,300 watts/746 could give you 1.7 hp. Our basis for computation would always be in watts because you would rarely see tools indicating their horsepower. Horsepower is the measurement of power that the machine can generate.


Power Capacities of Angle Grinders

If you want to buy your grinder and wanted to know the right angle grinder size for your work, we have put up the list here of the many sizes of the grinders. These include their wattage and capacity in horsepower so that you will know which are the best for the DIYers and the professionals.

Note that even angle grinders are of the same size; their power also varies which you can see in their wattage. So what we have below are just examples of the size and capacities of the grinders that run on 120 and 230 volts power.  

In 120 Volts:

4.5 inch (115mm) – from 700-1,300 watts (5.8 -10.8 amps) – .9 – 1.7 hp  (10,000 to 11,000 rpm)

Available are corded and cordless. This angler grinder size is best for polishing metal sheets, cutting small pieces of metal, refining excess weld, and for cutting floor tiles. This is the most practical choice for your home workshop/garage use.  

With a powerful spinning capacity of up to 11,000 rpm and an average weight of 3.5 lbs, this is best to keep for personal use. Very easy to use and very portable, even beginners would be able to handle it skillfully.  

5 inch (125mm) – from 1,400-1,600 watts (11.5-13.3 amps) – 1.8 hp – 2.14 hp (11,000 to 11,500 rpm)

The 5-inch angle grinder is not far from the size of the 4.5-inch but is packed with more amps and therefore is also packed with more power and speed and can meet the demand for grinding and cutting work on a bit larger scale. Still belongs in the small size category, its size would be perfect if you are working on a small metal welding business. Though we’ve seen a number of them being used by bricklayers, metal polishers and home restorers, if you go from a DIYer into business, you should consider this size.


6 inch (150mm) – from 1,400-1,500 watts (11.5 – 12.5 amps) – 1.8– 2.0 hp (4,000 to 9,000 rpm)

With a bigger motor, you could use this size for cutting stones, hard plastic, aluminum, and of course it can do what its smaller counterparts can do on a faster and bigger scale. Though this size is not very common as most angle grinder users who do their projects in their garage prefer the 4.5-inch, the 6-inch is more of a cut-off between the 7-inch and the 5-inch which are basically in the small to the medium-size category.  

Almost the same capacity as the 5-inch angle grinder, this is, however, a lot bigger than the 4.5-inch grinder and a bit heavier and more robust.

7 inch (180mm) – from 1,600 – 2,600 watts (13 – 16.5 amps) – 2.14 – 3.5 hp (6,000 to 8,500 rpm)

This is already a beast in the medium-size category. It can deal with bronze, aluminum, iron, die-cast metals and can also cut softer steel as well as concrete and any type of stone materials. 

With a greater angle grinder wattage, this could provide you an increase in performance with high overload durability. More compact than the 9-inch, it is also lighter but the size of its motor can deliver better performance even on tougher jobs. 


welding bevels

It is, therefore, the better choice for construction workers, plumbers, electricians, HVAC, tile workers, and welders. It could also convenient anyone who is working on construction sites, building renovation and metal fabrication. 

If your hands can’t carry the bulky 9-inch angle grinder the whole day, this heavy-duty angle grinder size could do some of its jobs as it is lighter by a few pounds. 

In 230-240 volts:

9 inch (230mm) – from 1,200 – 2,400 watts (10 – 20.8 amps) 1.6 – 3.20 hp (6,000 to 6,600 rpm)

This angle grinder size usually runs at 230 to 240 volts and it is available in a variety of amps and power. It generally needs a higher voltage because it has a large motor which enables it to be used for heavy grinding work both for concrete and metalwork purposes. 

This is usually preferred by professional welders, masons, automotive technicians, shipyard workers, general contractors, fabricators and other workers who are in the industrial grinding sectors and it can deal efficiently with the hardest and largest stones and metal. Large but very versatile, it can put up to 3.5 hp. So even cutting large metal pipes and bars could be easy with this large tool.


I know that a lot of you out there wanted badly to have the best angle grinder but some of you may still want to know the size you need. 

Angle grinder size comes in a variety of sizes. But don’t get confused because there are only 3 sizes, namely the 4.5-inch, 7-inch and the 9-inch you could best choose from.  

The 4.5-inch is mainly for home and domestic use. The 7-inch will suit your need if you want to do home repair jobs like plumbing, sprinkler installation, and such. The 9-inch is perfect for professionals who are in the construction business, metal fabrication and other jobs that require the use of heavy-duty cutting and grinding tools.     

If you want to know the power of an angle grinder, start by checking the angle grinder wattage and you’ll get the idea on how strong the unit can be.