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How to Make Easy Half Square Triangles

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INSIDE: How to Make Easy Half Square Triangles

If you are new to quilting or want to learn more about quilting you need to know about the Half Square Triangle, commonly referred to as the HST. An HST is one of the most basic quilting blocks and can be used to create very complex quilts.

From this technique alone, a ton of designs can be created like Chevrons, Flying Geese, Herringbone, and ZigZag Path.

How to Make Easy Half Square Triangles Pin

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How to Make Easy Half Square Triangles

For new quilters there is no better skill-building block to master than half square triangles. They are a building block in many quilt designs and can be sized up or down as needed.

And once you’ve mastered how to make half square triangles, you can create a variety of quilts with just this block and some simple squares. It’s really that simple!

This image is a perfect example of how HSTs and squares can create a fun heart design. Notice how this block is just HSTs and squares. Now, imagine the possibilities!

heart shape made from hsts

Materials & Supplies:

*you will get perfectly flat seams when used together for pressing HSTs


Step 1: Cutting HSTs:

There are several different ways to cut and sew HSTs. I’m only going to show you one of the simplest methods, cutting two at a time. Eventually, I’ll introduce some of the other ways to create HSTs.

To create an HST you start with a light and a dark fabric. The greater the contrast the better the design will show up. For these instructions I am working with 6.5″ x 6.5″ squares (which is pretty standard for HSTs).

One thing to note: For the two at a time method, you can make your HST’s any size. Once you know the size of the HST’s you’ll be using in your design, cut the two squares 1″ larger than the finished size you’ll be using. For example, if you need your HSTs to be 5 1/2″ each, cut your squares 6 1/2″ each.

Diagram 1.

Place a light and a dark fabric square right sides together.

Diagram 2.

Use a pencil or water soluble marker, draw a diagonal line from one corner to the opposite corner. Personally, I prefer a pencil, but this will ultimately depend on the fabric you’re using.

Diagram 3.

On both sides of the diagonal line, stitch a scant 1/4″ seam. See How to Sew the Perfect Quilting Seam Allowance for more details.

Diagram 4.

Using a quilter’s ruler and rotary cutter, cut along the pencil line.

How to Make Half Square Triangles diagram

Once separated and unfolded, you will have two HSTs that each have a light and dark value triangle.

How to Make Easy Half Square Triangles

Step 2: Trimming the HST

Trim the HST down to the correct size using a square quilting ruler. Use a rotary cutter and quilter’s ruler to cut these away. Place the diagonal line on the ruler across the quilt block and then line it up to the size your want. Trim using a rotary cutter and mat.

creative grids ruler

You can see that this ruler allows you to cut several different sized HSTs just by flipping the ruler over. It’s my go-to ruler for all things HST.


Step 3: Laying out a design

Once you have all of your HSTs trimmed it’s now time to create a design. Since there are so many different designs I could use, I’m demonstrating using the classic Pinwheel quilt block.

Notice in Diagram 6. when the HSTs are sewn together it creates the beginning of a block seen in Diagram 7. When you connect the two pieces in Diagram 7 together it creates a larger Pinwheel block.

How to Make Half Square Triangles diagram
How to Make Half Square Triangles

Once your blocks are finished it’s time to start creating your design.


Turning HSTs into a Quilt:

After cutting out all of your HSTs it’s time to create a design. This can be done by tacking some quilt batting to the wall and laying out the Pinwheel blocks until you’ve created a design you prefer.

Did you know that Half Square Triangles are one of the most basic quilting blocks and can be used to create very complex blocks. From this technique alone a ton of designs can be created like Chevrons, Flying Geese, Herringbone, and ZigZag Path. This tutorial will explain to you about half-square triangles and how easy they are to make designs.

In my mind, the possibilities are endless. Because the Pinwheel design is four-patch, you could create blocks made up of four smaller pinwheels. There really is no limit to what you can make!


You can learn a lot about quilt design by playing with HST’s. The biggest takeaway will likely be color value. In order to create the true light/dark affect with HSTs be sure you have enough contrast between lighter and darker value fabrics.

Isn’t it true with any art form we embrace; it’s never about making something perfect, but always about the process.

Here’s a fun bit of homework. Go to Pinterest and type “HST Designs” in the search box. You will be amazed at all of the the beautiful designs that can be created using half square triangles.


>>> Want a printable version of the post? Click the pink button for the downloadable the Printable PDF instructions.

Half Square Triangles Printable Post Cover

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