Half square triangles are one of the most common units in patchwork quilting. It consists of two 90 degree triangles sewn into a square.

Once you start looking, you'll see the half square triangle in many different quilt blocks.

Last month, I shared how to make half square triangles two at a time. But for those projects where you need lots of them, I recommend trying this 8 at a time method.

I used all these HST's for a shoo-fly quilt block.

PLUS get a free printable cutting list for multiple sized blocks!

This method works great for a bear paw block too!

Sometimes it's called the magic 8 method. You begin with two squares of fabric and sew 4 seams along the diagonals. Cut the material in specific directions and magically, you will have 8 half square triangles.

Don't need 8? Try this 4 at a time method.

Keep reading for all the details!

HOW TO MAKE A HALF SQUARE TRIANGLE

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image with 8 half square triangles with text overlay

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Find the perfect half square triangle quilt to make in this article.

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SUPPLIES FOR HALF SQUARE TRIANGLES

fabric
thread
rotary cutter / cutting mat / straight edge
sewing machine
sewing scissors
pencil
iron and ironing board
square quilting rulers

HALF SQUARE TRIANGLE CHART

In order to end with the desired size of half square triangles there's a formula.

Finished size + 1 inch X 2 = Size square to cut

Many quilters add 7/8 of an inch instead of a full inch. But that just makes the math too complicated for me. Plus that extra 1/8 of an inch allows you to square up your pieces for optimal fit when piecing.

But you don't need to do the math! I've created a little cheat sheet for the most common block sizes. Go ahead to the bottom of the post to sign up to receive it right to your inbox. Then you can print it out for future reference.

HOW TO MAKE 8 HALF SQUARE TRIANGLES AT ONCE

Let's get started. As always, I have step-by-step pictures. Be sure to watch the video if you learn better that way.

collage of steps to make half square triangles

Begin with two equal sized squares of fabric. I like to use a darker fabric and a lighter fabric.

Place the darker fabric right side up. Lay the lighter fabric directly on top with the right side facing down.

Note: For this project I'm starting with 6" squares. The half square triangles will be trimmed to 2 1/2". Once sewn into the block their final size will be 2". Use the chart above to create the size HST's you need for your project.

tracing and sewing half square triangles

Now, take a straight edge and place it on top of the square corner to corner. Draw a line with a pencil. Repeat with opposite corners.

Sew along both sides of both lines. Use a 1/4 inch seam allowance.

collage depicting how to cut half square triangles

Next, we'll cut the square into four smaller squares. Cut both vertically and horizontally. Make sure you measure to be sure you cut them squarely in the center.

Next we'll cut each of the smaller squares into triangles. To do this cut along the drawn line.

Press them open and square them up. Now they're ready to go into a quilt project.

Want to watch the video? ↓↓Click the link ↓↓

→How to Make Half Square Triangles←