How to Cut and Sew 60° (Equilateral) Triangles

I used to be intimidated to sew with triangles, but after learning some helpful techniques and with practice, I realized that it wasn’t too hard! In this article I will show you how to cut equilateral, or 60° triangles, using a quilting ruler and rotary blade – it makes cutting the triangles super easy! I also share tips for accurately sewing the triangles together that can then be used for many different sewing projects.

I used my pieced together triangles that I later quilted to a layer of batting to make a super cute quilted zipper pouch. You can see how in my tutorial How To Sew a Lined Zipper Pouch. My bag pattern the Edgewood Sling Bag or this small quilted needle book would be great projects for these triangles.

My quilted bag pattern The Eva Quilted Tote and my patchwork Novi Stocking pattern were designed using 60° triangles – they’re both great small scale projects to practice piecing with triangles!

For more triangle practice with half square triangles head to my tutorial How to Make Half Square Triangles which are a little easier to make and work with. If you want to practice cutting and sewing with squares first then check out my two tutorials How to Cut Squares for Quilting and How to Sew Squares Together.

Let’s get started!

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Some Things You’ll Need

• Quilting ruler – My favorite ruler! It doesn’t have to be this exact one, but it should have degree measurements on it.
• Rotary blade
• Cutting mat
• Fabric – Quilting cotton is easiest to work with, but linen can also be used.

If you need an extra visual, then you can watch the YouTube video tutorial (below) or keep reading for the full written steps!

Cut Fabric Strips

First you’ll want to cut your fabric strips. The width of the strips will determine the size of your triangles – I’ve cut 3″ (7.6 cm) wide strips which make the finished triangles a scant 3 1/2″ (8.9 cm) on each side. *The sides will be a longer measurement than the strips since they’re cut on an angle.

The Eva Quilted Tote uses 4″ (10.2 cm) strips which makes the sides of the triangles 4 1/2″ (11.4 cm). The width of the fabric will determine how many triangles you can cut from one strip. For example: On 44/45” (112/149 cm) wide fabric, you can cut about 17-18 triangles from one strip when cutting 4″ (10.2 cm) strips.

The length of the strips is up to you and dependent on your project. I’m making a zipper pouch with these pieced triangles so I didn’t need very long strips. Let’s say you need a lot of triangles for a quilt – you can fold your fabric together selvage to selvage and cut the strips from the fold to the selvage edge.

Cut Out Triangles

Lay the fabric strip so the selvages are at the right. If you’re working with long strips you can keep the fabric folded in order to cut two at a time.

Orient the quilting ruler so that the 60° line is lined up along the bottom of the strip (see photo below). *If you’re left-handed, you may need to reverse these next few steps.

Holding the ruler firmly in place, cut along the edge of the ruler. You’ve made the first 60° angled side!

Turn the strip over (if the fabric has a definite wrong and right side, the wrong side will be facing up) so that the angled edge is on the left and angling up to the right (see photo below).

Line up the ruler again with the 60° line along the bottom edge of the strip. Cut along the edge of the ruler, and you have the first triangle! (Or the first two, if your fabric strip was folded in half).

The ruler that I’m using also has two lines that cross in the middle, so I can line up the point of the triangle in the 60° corner on the ruler – very handy! (This is only true when cutting from 3″ (7.6 cm) strips).

Turn the fabric strip over again so the angled edge is on the left and angling up to the right and line up the ruler along the 60° line at the bottom. By turning over the strip of fabric, it means you don’t have to keep adjusting or rotating the ruler.

Continue cutting out triangles in this way until you reach the end of the strip or have the desired amount in that fabric.

Sew Triangles Together

Before sewing the triangles together, lay them out and plan out your design. Once my design is final, I like to take a picture to remember it or in case it gets messed up somehow. Since I was making a zipper pouch with the quilted pieces I measured it up against the zipper length I was using to decide how many triangles I needed in each row.

*Keep in mind that the left and right edges will eventually be cut straight and the triangles at the end will be cut in half. You’ll see more what I mean on a later step.

Take the first two triangles at the beginning of the first row and pin them right sides together. Sew along the pinned edge with a scant 1/4″ (0.6 cm) seam allowance.

*In quilting, it’s common to sew with a scant 1/4″ seam allowance which helps achieve more accurate seams.

Pressing Seams

How you want to press your seams is personal preference and up to you. Pressing seams to the side creates some bulk at the seams, so it can be trickier to get neat triangle points, but it creates a stronger seam if you choose to quilt along the seam lines (aka “stitch in the ditch”).

Pressing the seams open is easier, especially for beginner quilters. It creates less bulk at the seams so the triangle points may turn out neater and it’s a lot easier to see where to line up the triangles points when sewing them together.

For reference, when I made my Eva Quilted Tote and Novi Stocking samples, I pressed all seams to the side. It is possible to get neat triangle points when pressing to the side but it does take accuracy and practice. I’ll show you both ways so you can decide which way you want to try or what will work best for your project.

Seams Pressed To The Side

Press the two triangles with the seams towards one direction. You will noticed that there is a bit sticking out at the ends – that’s ok! From here, you will be sewing the triangles in pairs. Depending on the amount of triangles in each row, you may have one on it’s own.

You can save time by chain piecing which is a quick and efficient way to piece fabric shapes together. All you do is, after sewing the first pair, continue sewing without lifting the presser foot and sew right onto the next pair. You end up with a garland of triangles which you can cut apart in between the pairs after sewing.

Once you have your triangle pairs sewn together, press them with the seam allowances going in one direction. I like to press each pair in the same direction in one row and then the opposite direction in the next row.

When lining up the triangles to sew, line them up from point to point (see photo below).

With some triangle pairs, you may need to unfold the pressed seam allowances in order to match up the triangle points. After lining up the points and pinning, put the seam allowance back in the direction it was previously pressed.

The tip of the triangle will stick out (at either the top or the bottom) but thats ok! Pin together two triangle pairs and sew with a scant 1/4″ (0.6 cm) seam allowance.

Keep adding triangle pairs until the row is the desired length and press flat.

Since my rows were made up of an odd number of triangles, I needed to add a single triangle at the end after sewing all the pairs together. Remember to line up the points of the triangles and sew with a scant 1/4″ (0.6 cm) seam allowance (see photos below).

Seams Pressed Open

After you sew two triangles together, press the seams open. I usually finger press first, press with the iron and then press one more time on the right side.

Next, line up two triangle pairs together, lining up the raw edges of the edge you will be sewing.

Line up the point of the triangles together. When the seams are pressed open, you don’t need to unfold any seam allowances (like you do when the seams are pressed to the side), but just line up the triangle point to the left of the seam with the corresponding triangle point underneath. (see photo below)

Pin triangle pairs together, usually one at each end.

Sew the triangle pairs together with a scant 1/4″ (0.6 cm) seam allowance. You will be sewing right through the intersection of the triangle points at the beginning and end of the edge.

Press the seams open. Then continue on with the rest of the row, sewing triangle pairs onto the next triangle.

Sew Rows Together

Once you have all your triangles sewn up in rows, it’s time to sew the rows together!

Place the rows right sides together, lining up the straight edge, and matching up the points of the triangles together and at each end.

Pin the rows together using plenty of pins to make sure everything lines up well. I like to place a pin right at the tip of the triangle stitch line.

Sew the rows together with a scant 1/4″ (0.6 cm) seam allowance. While sewing, make sure to not sew through the previous stitch line of the triangles – Sew just to the right of the tip of the triangle stitch line.

Press the two rows flat with the seam allowances going in one direction. Continue to sew rows together in this way until you reach the desired size for your project!

For a zipper pouch, I only needed three rows with 7 triangles in each row.

The Eva Quilted Tote has 5 rows with 7 triangles in each row for each Main Panel.

Trim off Edges

If you’re making something square or rectangular, like a quilt, the Eva Quilted Tote, or zipper pouch, you will need to cut off the edges to the dimension you need.

I’m using a 8″ (20.3 cm) zipper and the total length of the zipper is about 8.5″ (21.6 cm). It worked out pretty well that my rows ended up just about the same length as the zipper. 🙂

Since I’m using 1/4″ (0.6 cm) seam allowances for my zipper pouch, I included that amount before cutting by using the bit of seam allowance sticking out at the top as a guide (see photo below).

Cut off each side of the pieced triangles using a ruler and rotary blade, making sure to keep everything straight.

Then, using the ends you just cut as a guide, cut off the bits on the other sides to finish squaring up the rectangle. For reference, my finished rectangle ended up being 8 5/8″ wide and 7 1/4″ tall ( 21.9 cm x 18.4 cm). Then I quilted a layer of batting to the wrong side and used it as my outer fabric for my lined zipper pouch!

And you’re done! If you’re following along for the Eva Quilted Tote, then the next step is pinning your pieced panels to a layer of batting, and then quilting your desired pattern.

I hope this tutorial was helpful and gave you some confidence to sew with equilateral triangles! Thanks for reading and happy sewing 🙂