Patchwork & Appliqué

Discover How to Trim Perfect Half-Squares

Craftsy quilting instructor of Pre-Cut Piecing Made SimpleCamille Roskelley has creative techniques for staying organized and saving time, so that you can enjoy being creative even if your schedule is hectic. Here, she shows you how to trim your half-square triangles.

Hello, I’m Camille Roskelley a quilting instructor at Craftsy. Today I’m going to show you a little trick to cut your half-square triangles down.

Alright we’re going to cut this; we’re going to trim it to 4 inches. So the first thing we’re going to do is line this up on the 45 degree line on my mat and then center it. There are 4 inches here and I’m just going to center that on the 4 inch line.

So I can trim this on each side. Count over four, and trim the other side. Then I’m going to come up here and trim that. And then count down four more. This is on a half line so 1,2,3,4 and trim. And that’s the last side.

And now I have a perfect half-square triangle that measures four inches, which is not easy. If you liked this tip you might enjoy my class Pre-Cut Piecing Made Simple over at Craftsy. Check it out!

In case you missed learning about Camille and her quilting inspiration head here, and then come back to the Craftsy blog on Thursday for another great tip from Camille.


Pat Marcum

Such a quick and easy and accurate cut, thanks for sharing.


I have always been a ruler person not a mat person. I like to measure my HST with my ruler and align the 45 degree angle on the middle seam. Much more accurate!


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