Quarter Square Triangles: the most popular method

two quarter square triangles with title.

Quarter square triangles are squares made by stitching together four equal triangles. They are sometimes called hourglass blocks.

This method is the most popular for a reason – it is easy and makes two at a time with little waste.


You will need two squares of fabric – one light and one dark.

Cut the squares 1-1/2″ larger than the finished size piece you want.

For example, I want my final size to be 4″ when it is pieced in a quilt, so I will cut the squares 5-1/2″.

fabric for quarter square triangle.


On the back of the light square, mark a diagonal line.

fabric marked for stitching.
fabric stitched on diagonal.


Place the two squares right sides together and stitch 1/4″ away on both sides of the marked line.

making half square triangles.

Open and press to the dark side. You will have two half square triangles.

two half square triangles.

Place right sides together, putting light fabric to dark fabric. The pressed seam allowance will help them stay straight.

joining two half square triangles.

On one side, mark a diagonal line.

squares marked for stitching.

Stitch 1/4″ away on both sides of the line.

stitched quarter square triangles.

Open and press.

Square up

You will have to square up the finished unit. Because we want the piece to be 4″ square in the quilt, we need it to be 4-1/2″ square with seam allowances.

To square up, align the 45* line of the ruler with the diagonal line. Make sure that the centre intersection of the triangles is 2-1/4″ from the edge of the square.

Trim each of the sides.

squaring up quarter square triangles.

You’re done!

You have two perfectly sized quarter square triangle units.

two quarter square triangles.

What’s good

  • easy to do
  • makes 2 at a time
  • perfect result
  • little waste

What’s not good

  • trimming takes time
  • have to remember the math

When to use this method

  • when you need a lot of QST units
  • if you are using pre-cut squares

Rating: 4 out of 5

This method is not difficult to do and it gives a perfect result every time. It’s the most popular method for a reason.

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assorted pieced triangles with title.

blue fabric pieced triangles with title "half square triangles".

Elizabeth DeCroos - Epida Studio.

Elizabeth DeCroos

Elizabeth DeCroos is the designer and teacher at Epida Studio. She loves to work in quilting, pojagi and embroidery and teach these techniques to others.
Learn more and get her to speak to your group.

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