How to Sew a Square in a Square Block

Square in a square blocks are fun to sew. They are pretty easy and I love including them in my patterns.

I thought it was time to write a little "how to" for you on this beginner friendly quilt block.

First, what is a square in a square?

The square in a square block is just that! A square on point inside another square. See the image below. These blocks were from the Colored Glass Quilt which also incorporates this block.

There are a couple different ways to sew this block. I am showing you the no waste way, which means no fabric is thrown away.

The Math

Let's start with the math so you know how to cut your fabrics. I always like to make mine with scraps first to make sure all my math is correct because even 1/8th of an inch can make a difference in the finished size.

I have seen different charts and formulas for how to get the math for these blocks. This is the formula I use:
Take the finished size of the inside square (this is when the square is sewn in). Divide the number by 1.414 then add .875 or 7/8 inch. Then, round to the nearest number on your ruler.

So if my inside square is 4 inches. It's finished size is 3 1/2 inches. If I divide and add like above then round to the second decimal place I come away with 3.35. Rounding up my answer would be 3 3/8 inches.

If this is way to much math for you then I have a nifty calculator for you! Quilter's Paradise made a calculator to do all the math. Here is a link.

I haven't tried this calculator myself. But I regularly use their binding and backing calculators so I trust it would be accurate.

Let's Cut Fabrics

Using the math above, I cut my squares. The white square is 4 inches and the accent squares are 3 3/8 inches.

Cut the accent squares in half on the diagonal.

Find the center of the sides of the white square and the center of the long sides of the triangle. I do this by folding them in half and making a slight crease.


Then, line up the creases with the fabrics right sides together. Pin in place.


Sew 1/4 inch away from the edge of the fabric. Press seams outward and cut off the little dog ears on the sides.

Next, find the center of the sides of the 4 in. x 4 in. square and the long side of the accent triangles again by giving them a small crease. Line up the creases with the fabrics right sides together. Pin in place.

Sew on each side.


Press seams outward.


Trim off the dog ears on the sides.

It's important with square in a square blocks that there is a quarter inch of overlap of the accent fabric on each side. If there isn't then when the block is sewn into your project the point will disappear. 


I hope this helps! If you have any questions feel free to contact me.

Also, try out my patterns which include the square in a square block, Colored Glass and Hidden Shapes.



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