How to Cut Trim Angles Without Cutting Corners

When it comes to home projects, good trim work makes the difference between a beautiful room and one that looks haphazardly thrown together. While installing molding and other types of trim is straightforward and easy, the actual cutting work can be intimidating, even for a seasoned home craftsman. 

Today, we’ll cover everything you need to know about how to cut trim angles. When you’re finished, you should feel much more confident in your ability to cut the angles you need to produce beautiful trim work.

What You’ll Need

When it comes to cutting trim, you’ll be able to get the job done with little more than a compound miter saw. Other saws, like a circular saw or table saw can get the job done, but they’re not nearly as good at cutting precision trim work as a miter saw is.

For this project, I recommend you rent or borrow a compound miter saw if you don’t already have one, rather than trying to make it work with what you have on hand.

Step I: Identifying the Cut You Need

The first step in cutting trim is going to be identifying the angle you need to cut. The most popular angles for interior trim are 90° and 135° degrees, and each of those angles can be straight on, or with a bullnose.

The video above provides a great cheat sheet that makes it even easier for you to identify exactly what angle you need to cut. Or, if you need a cheat sheet for all the complex angles you’ll (hopefully) never need to worry about, Dewalt offers a more comprehensive sheet.

For the sake of this lesson, let’s say that we’re working on the trim for an interior wall with a 90° angle.

Step II: Cutting the Trim


When it comes to cutting the trim, using a regular miter saw can be difficult, or in some cases, impossible. With a standard miter saw, you’ll need to make your cut vertically through the trim. For thicker pieces of trim, this may not be realistic.

But, with a compound miter saw, you’ll be able to lay the trim flat against the fence of the saw, and adjust the head of the saw to the angle you need to cut. This makes cutting trim significantly easier.

A compound miter saw is something to consider investing in. But, if you don’t want to buy one, renting or borrowing one for the day will be perfect for the sake of this project.

Once you’re ready to begin cutting, you’ll want to put on your safety goggles and work gloves. You may also want to consider wearing earplugs.

First Cut

In this example, we’re cutting trim for a 90° inside corner. You’ll need to cut each piece of trim at a 45° angle so that when the two pieces butt together, they’ll create the perfect 90° angle you need to create a polished look. So, your first step is to set the saw to 45°.

Next, place the trim against the fence, so that the top of the trim is in contact with the fence. Since we’re cutting for an inside corner, you’ll want to make your cut on the right side of the piece of trim.

With the trim firmly against the fence, turn the saw on and make your first cut. Always keep the hand you’re holding the trim with at least 6” away from the blade of the saw.

Second Cut

Next, you’re going to repeat the process with the other piece of trim you’ll need to complete the corner. However, instead of holding the top of the trim against the fence, you’re going to do the reverse of that with this second piece. Place the trim against the fence so that the bottom of the trim butts up against the fence.

Now, you can make your second cut.

Outside Corners

If we were cutting trim for an outside corner instead of an inside corner, the entire process is identical. However, instead of angling the cut from front to back, the cut angles from back to front. To do this, you’ll simply cut from the left side of the trim, instead of the right side, as we did for an interior corner.

For other angled cuts, it’s as simple as setting your saw to cut the appropriate angle, and working from either the left or right side of the wood in order to produce a piece of trim for an inside or outside angle.

Final Word

Learning how to cut trim angles is a critical skill that every DIYer needs in their toolbox. Quality trim work can make a huge difference in the overall appearance and beauty of your home. After this lesson, you should be feeling a bit more like a seasoned pro when it comes to trim.

For more info on cutting and installing beautiful trim and molding, check out Home Depot’s helpful infographic.

About Gus Donaldson

I built houses for over 30 years and recently retired. I've made lots of mistakes and hopefully teach you not to make the same ones. I still love to build and have a garage workshop that I use for hobby projects like the walnut bookshelf I made for my wife. I like to write and let people know that working with your hands and tools does not need to be intimidating.

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