Bryan House Quilts

Triangle in a Square {Tutorial}

design improv with triangles· finished quilts· Modern Triangle Quilts· Tutorial

Hey guys!

Today, I’m sharing a triangle quilt tutorial. This tutorial will show you how to turn a Modern Triangle into a Square Block. I published this tutorial as part of my online workshop, Design Impov with Triangles. But I’ve had a couple of requests for this tutorial outside of that workshop, especially for those of you who enjoyed making the Heart Triangle.

Make this free heart triangle quilt block!

So, if you’ve made one equilateral triangle, or several (they can be like candy!), this is how you can turn your triangles into square minis. And if you’d like to learn how to design your own triangles, grab a spot on the waitlist and I’ll let you know when enrollment opens.

Enjoy!

This triangle quilt tutorial is based on the Equilateral Sampler pattern on page 44 of Modern Triangle Quilts. This version has pictures, a few more images and tips, and instructions and fabric requirements for mini quilts in multiples of 3. (So if you want to make 6 minis then double the recipe so to speak.)

Materials for Three Mini Quilts:

  • Three 8 1/2” equilateral triangle blocks
  • 1/2 yard of background fabric for every 3 triangles
  • 3 squares 20” x 20” backing
  • 3 squares 20” x 20” batting
  • 1/2 yard for binding for every 3 mini quilts

Cutting

From the background fabric cut:

  • Cut 2 strips 7” x fabric width. From each strip, subcut 3 rectangles 7” x 13 1/2” for a total of 6 rectangles.
  • Cut 1 strip 2 1/2” x fabric width. From each strip subcut 3 rectangles 2 1/2” x 12 1/2” for a total of 3 strips

Piecing

1. Make your equilateral blocks either by following the instructions in Modern Triangle Quilts (pages 15-43) or by creating your own designs within the Design Improv with Triangles.

2. Trim off the lower right corner from each background rectangle: Mark 1” from the corner on the long side and 1 3/4”from the corner on the short side. (Important note: If you are using printed fabric, you will need to trim the corners from the rectangles a bit differently: 36 of the rectangles should have the lower right corner trimmed, while the other 36 should have the lower left corner trimmed.)

3. For each block, lay out 2 mirrored trimmed rectangles on the sides and 1 background 2 1/2” x 12 1/2” strips along the bottom of the block.

4. Add the left background piece.

Tip: Notice in the picture to the left, the wee pink triangle sticking out? This is the dog ear and I’m looking for it to extend past the background piece by roughly 1/4”.

My favorite trick is to use my acrylic ruler, or add-a-quarter ruler to measure how far the dog ear sticks out.

You can see in the picture on the right, where the pin is pointing, that the dog ear sticks out about 1/4” beyond the background.

Note that this doesn’t have to be perfect all the time. There is some room to fudge here and there.

triangle quilt tutorial

Optional: Consider pinning the pieces together before sewing.

I don’t usually pin, but I’ve pieced angles a TON of times. When I was a beginner I did pin. So, if you are a newer piecing or new to piecing with angles, you might want to pin.

4a. Sew and press the seam toward the triangle.

4b. Trim the excess fabric from the rectangle as shown above.

5. Add the right background piece in the same manner. Notice the dog ear sticking out roughly 1/4” beyond the background piece in the lower right corner of the triangle in the above picture?

Same trick with the acrylic ruler. If necessary pin the pieces together and then sew.

Press the seams toward the background.

6. Lastly center and add the 2 1/2” x 12 1/2” strip to the bottom of the triangle. To center the pieces, fold the strip in half and finger-press to mark the center. Also do this with the triangle.

Press the seam toward the background.

7. Square up the block to 12 1/2” x 12 1/2”. Use the 2 1/2” x 12 1/2” strip at the bottom to guide you. Line up the base of the block (shown as the left side of the block as pictured above) with a line on your cutting mat.

7a. Trim the right side of the block.

7b. Trim the left side of the block.

triangle quilt tutorial

Finishing

1. Make or cut 3 backings, 20” x 20”.

2. Baste and quilt as desired. (Hint: Use some of the line motifs you explored or use some of the textures you’ll explore in Lesson 5 (of Design Improv with Triangles): Layering and Texture.

3. Bind the mini using your preferred method and upload a picture for us to oogle in a “Show your Work” page.

Want more Modern Triangle Quilts?

I hope you find this triangle quilt tutorial useful! Whether you are interested in designing your own modern triangle quilts or you simply want to make a modern triangle quilt, I’ve got so many fun options for you to explore!