I’ve figured out a simple way to make a lot of Square in a Triangle units. And I thought I’d share the basic instructions to help anyone that needs to make a lot of them.

First you need to decide on the size of the square that will be in the triangle. In my example I cut a 2 1/2″ square, but you could make it any size. Cut one strip of fabric at 2 1/2″ The second strip of fabric, in a contrasting color will be cut 3/4″ larger than the first strip. In this case 3 1/4″. Sew the two strips together, lengthwise with a 1/4″ seam and press to the larger strip. (For other sizes, the size of your strips would be 1 1/2″ and 2 1/4″ or 2″ and 2 3/4″ or 3″ and 3 3/4″, etc.)

Next you will sub-cut the strip sets to the size of your square. In this example it is 2 1/2″. Again, the sub-cutting would be to the size that you want your square ( 1 1/2″ or 2″ or 3″, etc.)

Take two of the sub-cut units and sew together with the squares on either end.

Now, at this point, if you just need to cut this into triangles you can use the Easy Angle ruler, or whichever ruler works for you, to cut a half square triangle. I’ll show the cutting in a minute. But I want to show how to add a larger triangle to make a square unit.

In this example you now have a unit that measures 4 1/2″ x 5 1/4″ Cut a piece of fabric that should actually contrast from your little triangle pieces. But since I was doing this in a hurry and late at night, I screwed up and cut it out of neutral fabric. Use your imagination and picture the large rectangle as being red.

Layer them together, then cut with the Easy Angle ruler. In this example I used the 4 1/2″ markings for my triangles. If your square started at 1 1/2″ you would use the 2 1/2″ markings. If your square started at 2″ you would use the 3 1/2″ markings. If your square started at 3″ you would use the 5 1/2″, etc.


Now sew the bias edges with 1/4″ seam and press to the large triangle. I’m showing the back of one block to show how the seams are pressed, but this is slightly misleading. Back when you sew the two sub-cut units into the 4 1/2″ x 5 1/4″ unit, and then when you cut it with the Easy Angle ruler, you’re going to have one unit with both seams of the square pressed out to the small triangles, but the other unit will have one seam pressed out and one seam pressed in. You will been to re-press that seam so that the both are pressed out.


I hope this all makes sense. I was excited to figure this out and wanted to share it right away. But it is past my usual nighty-nite time and I might have thought I was being clear when I really wasn’t. If you have any questions, leave a comment and I’ll answer as soon as possible.

Peace