How to Make Half Rectangle Triangles (HRTs) | A Quilter’s Guide

Half rectangle triangles (HRTs) are one of those intermediate quilting skills that can seem tricky at first, but once you’ve made a few and learn the right trimming method, they become incredibly satisfying and versatile. If you’re working through the Dilly Dally Quilt, you’ll get lots of hands-on practice. Four of the blocks in the quilt use HRTs!
Today, I’m sharing a new video tutorial from the Dilly Dally Quilt Class where I walk you step by step through how to make HRTs. This is a great warm-up before you begin your HRT blocks.
HRTs vs. Half Square Triangles: What’s the Difference?
While HRTs and half square triangles (HSTs) may look similar, they’re constructed differently and can’t be used interchangeably. Here are a few key differences:
- Shape: HRTs are longer and leaner, they are rectangular instead of square.
- Construction: You start with rectangles, not squares.
- Seam direction matters: The direction you draw your diagonal line will change the final angle of your triangle.
- Trimming is more precise: Because of their proportions, HRTs require more careful trimming to ensure accuracy.
Want to explore HRT-heavy quilts? Check out my patterns:
My Favorite Way to Trim Half Rectangle Triangles
In the video, I demonstrate a trimming method that has completely changed how I work with HRTs. Here’s a quick breakdown:
- Use washi tape to mark the unfinished size on your quilting ruler.
- With a Sharpie, mark dots a ¼” in from each corner of your rectangle on the ruler.
- Line those dots up with the seam line of your pressed HRT.
- Trim with precision!
Don’t worry—Sharpie comes off with nail polish remover. This trick has helped me stay consistent and avoid wonky HRTs.
Video Links
- My Pressing Station (underneath my wool mat, I have a flannel/vinyl tablecloth protecting the table):
- Cutting Station
- Sewing Machine Station
Make One First, Before Starting Your Block
If you’re following along with Dilly Dally Quilt, I strongly encourage you to make a single HRT before diving into your first full block. It gives you a chance to test your angles, trimming, and pressing techniques without committing to the whole layout just yet.
Half rectangle triangles are a skill worth mastering, especially if you’re looking to take your quilt designs beyond the basics. With the right prep and a good trimming method, they’ll become one of your favorite units to work with.
🧵 Start your HRT journey with Dilly Dally Quilt or try one of my other patterns featuring this block style.