How to Cut a 45-Degree Angle With a Circular Saw (Step-by-Step)

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Square joints and those clean 45-degree angle cuts are a common yet essential part of various trimming projects. I’ve encountered them countless times in my own work. But can you achieve these with a circular saw? Absolutely.

You might be tempted to dive right in and figure it out through trial and error, but I’m here to save you the hassle. In this guide, I’ll be walking you through the process of making those precise 45-degree cuts using a circular saw!

Bevel vs. Miter 45-Degree Cuts

Most circular saws are capable of executing bevel and miter cuts. However, before you start cutting, it’s important to note their differences. 

If you need to do a miter cut, you’ll need to deal with the square side of the wood board. The entire cut must be done from the wood’s top to face down. 

bevel cut

On the other hand, cutting a 45-degree bevel cut on the face of the wood. If you want accurate cuts, you must only begin cutting when both wood pieces are in a 90-degree cut line. 

Tools and Materials You’ll Need

Method #1: Making a 45-Degree Bevel With a Circular Saw (Length and Width)

Step #1: Draw the Cutting Line

You can only achieve a clean bevel angle cut if your circular saw blade is in perfect alignment. I highly recommend using a speed square for accurately measuring and marking the cut line on any workpiece. Trust me, it makes a world of difference.

See Also: How Do You Measure and Cut 45-Degree Angle Cuts in Wood 

It’s a pretty straightforward process, so you must carefully line the wood board for a cleaner cut. 

Step #2: Clamp the Square

After you measure and mark the cut line with a speed square, it’s time to place your circular saw on the wood piece. You must align the line you drew earlier with the kerf indicator near the saw’s shoe.

If you look closer, you’ll see that you can choose between two lines: the 0 or the 45-degree option. Choose the latter if you’re aiming for an accurate angle. 

cutting 45 degree angle with circular saw

Next, put the speed square next to the shoe and clamp them together. It will serve as an angle guide to get the perfect cut. 

Step #3: Set Your Circular Saw’s Bevel and Depth

To cut 45-degree angles, you must adjust the bevel angle and cutting depth. Depending on what kind of circular saw, you can set the blade angle in detents like 45-degree or 22.5-degree. 

After you adjust the circular saw to a 45-degree angle, find the depth adjusting knob. I suggest doing this to let the saw blade stick out a bit underneath the wood surface. However, it’s not something you need to do if you’re aiming for a rough cut. 

Step #4: Cut Away

To avoid inaccuracies, re-check if the shoe is lined up firmly against the straight edge of the speed square. 

Carefully guide the circular saw as you cut the wood to prevent twisting tendencies that might cause your tool to stir away from the intended 45-degree angle.

cutting 45 degree angle

Step #5: Sand the Edges

After you’ve successfully cut 45-degree angle cuts on the wood board, remember to run a piece of sandpaper over the material’s edge to prevent splinters[1].  

Method #2: Making a 45-Degree Miter With a Circular Saw

Step #1: Draw the Trimming Line

As you did with the above method, you must mark the cut line using a speed square and pencil to get perfect cuts. Double check the square’s edge and ensure that you’re marking it at exactly 45 degrees.

Step #2: Clamp the Square

Unlike the beveling method, you should place the circular saw over the wood surface with the indicator set at 0 degrees. 

Once that’s done, ensure that the square’s bottom is against the shoe’s edge before clamping them. It’ll act as an angle guide as you perform the miter cut later. 

cutting 45 deg angle

Step #3: Set Your Circular Saw’s Blade Depth

Using a circular saw for these cuts is a bit like using a miter saw in this respect: there’s no need to fuss with bevel angles since the blade tackles the wood at a right angle. And a key tip: always slide the blade guard back before pressing it against the wood. It’s a simple move, but crucial for a smooth start to your cut. 

The blade depth must also extend around ¼-inch over the material’s bottom or overall thickness.

Step #4: Cut Away

Again, don’t forget to check the speed square’s straight edge alignment before slicing away. You can retract the blade guard from the circular saw to prevent any resistance during the cut.

Step #5: Polish the Cut

Once the material is cut, finish the task by sanding the sliced edge. You can use a typical sandpaper or wood file for this. 

polishing the angle

Method #3: Making a 45-Degree Compound Miter With a Circular Saw

Step #1: Draw the Trimming Line

It doesn’t matter if you’re making pieces for a window trim or cupboard—the reality is you need speed squares and pencils to mark the area you’ll be cutting with the blade. 

Step #2: Position the Square

Your tool’s shoe must be aligned at 45-degree angles, which you can verify through the indicator line. The square’s edge must be against the shoe to guide the blade in making compound miter cuts. 

Step #3: Set Your Saw’s Bevel Angle and Depth

In the front part of the circular saw, you should be able to set the bevel knobs to 45 degrees. I also suggest changing the blade depth configurations so that it can reach below the wood’s surface.  

Step #4: Cut Away

You must slowly point the blade’s edge to the line you marked earlier. Keep your focus on the saw base plate, and see to it that it doesn’t wobble until the compound miter cut is achieved. 

Besides that, wear protective gear during this process. Given that a circular saw runs with a sharp blade and produces dust, adding an extra layer of protection is necessary.

45 degree angle

Step #5: Sand

Lastly, grab a sanding paper or wood pile to smoothen the wood board’s edges. To avoid accidental blade contact, you must unplug and set aside the saw before doing this step. 

Other Ways to Make a 45-Degree Cut Using Your Circular Saw

T-Bar

You can opt to attach a T-bar to the power saw and adjust the tool’s position so that both components can align. The most important part of this method is setting the right angle, or the output won’t be precise.   

Miter Box

If you have a 2×4-inch miter box, that could aid you in cutting 45-degree cuts with a circular saw. It lessens the chances of errors when cutting wooden boards and plywood sheets. 

Straight Edge Guide

Admit it or not, you can’t cut 45° angles perfectly without an angle guide. 

straight edge

You can clamp the straight edges to the material to keep it firm and in place.  

Interesting Read: What Circular Saw Size Do You Need To Cut 4×4 Wood

Tips for Precise and Clean Cuts

Conclusion

Every seasoned woodworker eventually encounters the need to master the 45-degree angle cut using a circular saw, especially when we’re working with a limited toolset in the workshop.

That said, I can’t stress enough the value of doing a test cut on some scrap material first. The technique can be a bit finicky with this particular blade, so a trial run can make all the difference.

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Robert Johnson is a passionate furniture maker & carpenter, sought after for his knowledge on the craft.
You’ve probably seen his down-to-earth wisdom in USA Today, Bobvila, Family Handyman, and The Spruce, where he has shared commentary and guidance on various woodworking topics.

Robert is the brain behind Sawinery, where he aims to share tips, tricks, and a passion for all things carpentry.

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