Free Modern Half Square Triangle Quilt Pattern – 4 Ways


Half square triangles make gorgeous quilts! Sew a gorgeous throw quilt in no time at all using just one quilt block – the HST (or half square triangle).

Let me show you a shortcut method for making this easy 12” (finished) HST block. Sew 16 of them and then you decide what you want your 60” square throw quilt to look like. I’ll provide 4 layout ideas to get you started.

I placed a downloadble PDF of this quilt pattern in my PDF library of All SewCanShe Printable Blog Tutorials and Patterns. If you wish to print this free quilt pattern without purchasing the library, simply hit CTRL+P (everything you need is included in this blog post). You can get a free PDF file for the HST block pattern only here.

After I wrote the instructions for an easy HST quilt block, I wanted to show you options for this thow quilt. It’s:

  • super fast with only 16 blocks plus a border
  • totally easy patchwork
  • perfect for beginner quilters making their first quilt
  • great for a last minute gift
  • a great size to practice free motion quilting

How to Sew a Modern HST Quilt

These instructions make 16 HST blocks. Finished quilt dimensions: 60’’ x 60’’. Finished block size: 12” x 12”. My HST Block Pattern is also available as a free downloadable file. Get it here.

You will need:

  • 2 1/4 yards background fabric (suggested: light gray fabric)
  • 1 1/8 yards contrasting fabric* (suggested: coral colored fabric)
  • 1/2 yard binding fabric
  • 4 yards backing fabric, or enough to piece together a 68” x 68” square
  • a 68” x 68” piece of quilt batting
  • a rotary cutter, acrylic ruler, and mat
  • sewing machine
  • thread (I suggest thread matching the light gray fabric)

*For a scrappy quilt, choose lots of different contrasting fabrics!


Light Gray (or other background fabric):

  • cut 8 squares 13” x 13”
  • 2 border strips 6 1/2” x 48 1/2”**
  • 2 border strips 6 1/2” x 60 1/2”**

Deep Coral (or other contrasting fabric):

  • cut 8 squares 13” x 13”

Binding fabric:

  • cut 6-7 strips 2 1/2” x width of fabric (40-42’’)

** Border tips:

  • The border strips will need to be pieced together.
  • I highly recommend that you do not cut your border strips now. Instead, wait until the center of the quilt top is finished so you can measure it and sew accurate borders. See how to measure and cut accurate quilt borders.

Sew 16 HST Quilt Blocks:

Use a scant 1/4’’ seam allowance and a medium stitch length such as 2-2.5.

1. Place one light gray square and one deep coral square right sides together. Use a pencil or fabric pen to draw a diagonal line across the light gray square. This is a cutting line.

Pin the squares together.

2. Sew a scant 1/4’’ away from the cutting line on on both sides of the line.

3. Cut the piece in half diagonally along the line. 

4. Open and press the two blocks. Trim each block to 12 1/2’’. 

Repeat to make 16 blocks.

Trim and square your blocks to 12 1/2”.

Assemble the Quilt Top

1. Lay out your quilt blocks on using a quilt design wall, on a bed, or on the floor.

There are 4 rows, each with 4 blocks. Here’s one idea.

And here’s 3 more!

2. Sew 4 blocks into a row. Then sew 4 rows.

3. Sew the rows together.

4. Attach the borders. Sew the 6 1/2” x 48 1/2” border strips to the sides of the quilt. Sew the 6 1/2” x 60 1/2” border strips to the top and bottom edges of the quilt.

Tip: Instead of using the specified lengths for the border strips, I recommend measuring your quilt and using the actual measurements as I show in this blog post. This helps to prevent wavy quilt borders or puckering where the borders are attached.

Finishing your Modern HST Throw Quilt

1. Cut or piece together a 68’’ x 68’’ piece of backing fabric and make a quilt sandwich with the backing, batting, and top.

2. Baste together with fusible batting, pins or basting spray.

3. Quilt as desired. Straight line quilting with your walking foot would be fast and easy.

4. Cut 6 binding strips and bind using your favorite method. This is my favorite quilt binding method. Add one more binding strip if needed.

The HST Block is part of our Kitchen Sink Quiltalong

queen size quilt free pattern

Get ready to sew all your favorite quilt blocks this year! This is the year that we are going to sew everything but the kitchen sink in our Kitchen Sink 2022 Quiltalong.

This bold graphic quilt is perfect for learning new quilt making skills that build on one another, or for putting skills you already have into a big beautiful quilt.

Click here to learn about our Kitchen Sink Quiltalong.


Disclosure: some of my posts contain affiliate links. If you purchase something through one of those links I may receive a small commission, so thank you for supporting SewCanShe when you shop! All of the opinions are my own and I only suggest products that I actually use. 🙂