How to Make 2-at-a-Time Quarter Square Triangles

January 14, 2026

Quarter square triangles, also called hourglass blocks, are such a versatile unit for quilts and quilting projects! They are a main component of my new pattern called Two Peas. The pattern uses (2) fat quarters to make (2) inverse blocks that are as sweet two peas in a pod!

Get the pattern for free here!

Let's walk through the process of making these super fun quarter square triangle units! This method makes 2-at-a-time quarter square triangles (QSTs).

You will need (2) squares of contrasting fabrics. To calculate the size squares you need, just add 1.5" to your desired finished size. This will leave you with enough wiggle room to trim them up at the end, resulting in more accurate units.
For example: In my Two Peas block pattern, the finished size of the QSTs needs to be 3" x 3". This means that my starting squares will be 4.5" x 4.5".

On the wrong side of (1) square, mark a diagonal line from corner to corner.
Place that square, right sides together, with the second square.
Sew 1/4" away from BOTH sides of the drawn line.
Cut on the drawn line and press both pieces towards the darker fabric. You will have (2) half square triangles (HSTs). Do NOT trim them yet.
On the wrong side of (1) of the HSTs from the previous step, mark a diagonal line from corner to corner that is perpendicular to the stitched line. The stitched line and the drawn line should from an X through the center.
Place both HSTs right sides together, with opposite fabrics touching and nesting the diagonal seam. Sew a 1/4" away from BOTH sides of the drawn line.
Cut on the drawn line and press the seams open. You will have (2) matching QSTs. Trim both to your finished size + 1/2". (For the Two Peas pattern, the trim size is 3.5" x 3.5".)
I like to use my slotted trimmers to trim before I press the seams open. If you don't have the slotted trimmers, press open first and use a regular quilting ruler to trim them to size.