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Half Rectangle Triangles – Explained – Video Tutorial

Today’s post is part of a series called Quilt Block Building Basics.

Consider this a helpful visual and companion for any of my quilt patterns.  Sometimes you just need to see it to understand it.  

To view all previous posts in this series, click here.




Seems like last February when I published a video tutorial for how to use my Half Rectangle Triangle ruler. Since then, I’ve gotten better at using it. I’ve learned better ways of maneuvering and handy tricks to help myself out. This is what we are chatting about today!





  1.  No matter what size you need, you’ll add 1″ to the unfinished size you want your HRTs to be.  For example if I want to make 3.5×4.5″ half rectangle triangles, my starting rectangles will be 4.5×5.5″.  This ruler will make sizes 2×4″, all the way up to 4.5×8.5″.
  2.  It’s important that you draw your line in the right direction.  Follow your pattern.  My patterns will tell you which direction to draw the line and you usually need some in each direction.
  3.  Two rectangles sewn together will give you 2 HRTs with the seam in the SAME direction.  So unlike half square triangles, you can’t make the mirror image from one set (see #2).
  4.  Sew a scant 1/4″ on both sides of the drawn line.
  5.  Cut directly on drawn line creating 2 HRTs.
  6. Press seams open and don’t forget to starch.
  7. Trim each HRT using the ruler.


  • Don’t skip pressing seams open. It’s a lot harder to get trimmed correctly when pressed to one side.
  • The tape is really helpful in my opinion, give it a try and see what you think.
  • If you are using your HRTs for diamonds, add .25″ to the “trim to” size for length. After you sew top and bottom rows for the diamond, sew the two sets together with a 1/2″ seam.
  • Starch the devil out of your HRTs! Crisp patchwork = points lining up.

Tools Used in Video




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