How to Trim Half Rectangle Triangles (HRTs) the Easy Way (Perfect Points Every Time)
Half rectangle triangles (HRTs) are a versatile quilt block unit, but the can feel a little intimidating, especially when it comes to trimming them accurately. For a long time, trimming HRTs was the part I struggled with the most.
In this tutorial, I’m sharing my easy method for trimming half rectangle triangles so you can square them up quickly and keep those nice sharp points. No specialty rulers required. With a few simple steps, you'll be trimming HRTs confidently in no time!
If you’ve ever struggled with how to trim half rectangle triangles accurately, you’re not alone. Many quilters find HRTs tricky because the diagonal seam and rectangular shape make them harder to square up than half square triangles. This simple trimming method will help you square up half rectangle triangles quickly and keep your points crisp.
Prefer to see it in action? Watch the full tutorial below:
What you’ll need
Before we start trimming, gather the following tools and materials:
- Unfinished HRTs units
- A quilting ruler; large enough to cover your HRT size. I’m using a 6 ½" x 6 ½" ruler.
- Rotary cutter
- Cutting mat
- Marker (e.g. Sharpie). Use a marker that can be easily removed from your ruler.
Marking Your Ruler
Start with the unfinished HRT size from your pattern. For this tutorial, my unfinished HRT size is 2 ¼" x 3 ¾", which is the size I’ll be trimming to.
On your ruler, mark a small dot where the ¼" intersects, based on your trim-to size.
For this example, place dots at the following intersections:
- Top right: ¼" x ¼"
- Top left: 2" x ¼"
- Bottom left: 2" x 3 ½"
- Bottom right: ¼" x 3 ½"
You should now have four dots marked at the ¼" intersections on each corner of your trimming size. These dots will guide your ruler placement when trimming your HRTs.
Trimming the Left HRTs
1. Place your ruler on top of the HRT, lining up the diagonal seam line with the top left and bottom right dots on your ruler.
2. Trim the right and top edges of the HRT.
3. Rotate the HRT 180 degrees. Line up the diagonal seam with the top left and bottom right dots, making sure the trimmed edges align with your unfinished HRT size (in this example, 2 ¼" x 3 ¾").
4. Trim the right and top edges to square up your HRT.
Tip: Always keep your marked dots aligned with your diagonal seam before trimming — this is the key to accurate points.
Trimming the Right HRTs
1. Place your ruler on top of the HRT, lining up the diagonal seam line with the top right and bottom left dots on your ruler.
2. Trim the right and top edges of the HRT.
3. Rotate the HRT 180 degrees. Line up the diagonal seam with the top right and bottom left dots, ensuring the trimmed edges align with your unfinished HRT size.
4. Trim the right and top edges to complete your HRT.
Once you get the hang of trimming half rectangle triangles this way, they become so much easier to work with. They’re now one of my favourite quilt block units, and I hope this method helps you feel more confident using them too.
Remember — accurate trimming comes down to aligning your diagonal seam with your marked dots. That one step makes all the difference in keeping your points sharp.
Download Your HRT Trimming Cheat Sheet
To make trimming half rectangle triangles even easier, you can download a free copy of my HRT trimming guide or purchase a printable version for quick reference at your cutting table:
Keep it handy while you trim — it makes the process faster, more accurate, and stress-free!
