How to trim half square triangles (HST)

If you were to learn just one quilting block, I highly recommend mastering half square triangles (HSTs). With HSTs, whether used alone or in combination with plain squares, the possibilities for creating an array of quilt blocks are virtually endless—your imagination is the only limit!

Why trim your HSTs?

When sewing HSTs in batches, the resulting pieces often lack precision. To address this, I prefer to cut my starting squares slightly larger than the required size and then trim them down to the exact dimensions.

For example, if the HST formula suggests a starting square of 3 7/8”, I round it up to the next whole number, like 4”. This approach means I’ll need to trim later, but it ultimately leads to more accurate and satisfying results, reducing frustration.

Typically, I trim my half square triangles after pressing them. However, I’ve recently discovered a quicker method for this process.

I recommend using tape instead of a visual guide to trim down your HSTs. If tape isn’t available, that’s perfectly fine; just ensure your ruler hasn’t shifted before you make any cuts.

To see both techniques in action, be sure to check out my video tutorial!