Half Square Triangle Formula

Question

I want finished 2 1/2" half-square triangles. How big should I cut the beginning square piece?

Reply

To make half square triangles the exact size needed, add 7/8" to the size of the finished square.

For your project that means rotary cut your squares 3-3/8" x 3-3/8" (2-1/2" + 7/8" = 3-3/8").

Personally, I like to start with over-sized squares. After marking, sewing and pressing, then cut them down to the exact size. It's a bit more 'fiddly' and requires extra fabric, but then, if I'm a bit lax in my sewing, the units still come out perfect.

I've just finished uploading a page on how to make half square triangles. There are a few more pictures that I will be adding, but all the steps are there.

Over the next week or so, I'll add pages with other methods to create these versatile units.

Thank you for your question.

Piecefully,

Julie Baird
Editor

PS I've also found a neat ruler for cutting squares for half and quarter square triangles. With it, the only thing you need to remember is the finished size of the unit. You can read about it here at Wonder Ruler Quilting Ruler.