Tips for Half-Square Triangle Piecing

By National Quilters Circle Editors

Half square triangle piecing
If you’re tired of following someone else’s patterns and are ready to get creative with your quilt designs, half-square triangles are the perfect way to start. Using these simple two-piece blocks, you can create hundreds of different quilt top designs, from simple pinwheels to intricate portraits. Half-square triangles are the most versatile of all the basic quilt blocks. Using chain piecing methods, you can create dozens of basic blocks per hour, giving you the raw materials for creating your own artisan quilt tops.

What Are Half-Square Triangles?

This odd name describes a basic quilt block made up of two triangles, one light and one dark, sewn together so they create a square with a diagonal line from corner to corner. They give visual excitement to quilts because of the angles they create when pieced together in rows. This versatile design can make up any number of shapes on the quilt top, depending on which way you place the light and dark halves of the block.

Simple Half-Square Triangle Piecing

Traditional quilters used to cut out individual triangles to sew together, but you’ll save a lot of time using speed-piecing techniques. Here’s an easy way to do it: 1. Cut out squares of light and dark fabrics and pair them up, right sides together. 2. Draw a diagonal line from one corner to the other on the wrong side of the light material. 3. Sew ¼ inch away from this line, with one seam on each side. 4. Cut along this marked line, then open up each sewn triangle to find a perfect half-square triangle.
Steps for a Half Square Triangle
If you’d like to try a different method, check out this article for a detailed explanation.

Simple Quilt Top Patterns

This block is so versatile it’s almost impossible to make the same quilt top twice, and why would you want to? With this many possibilities, it’s hard to decide which one you want to make first. Some of the simplest patterns you can make are perfect for beginners, or for when you want to make a simple quilt as a gift. (Baby quilts, anyone?) Simple doesn’t always have to look plain though. Here are some ideas to spice up your designs:
  • Bright pinwheels on a white or black background can take on many feelings, depending on the fabrics
  • Twist and turn the colored fabrics to create a multitude of star patterns
  • Entire tops of half-square triangle rows can look elegant and modern when you show off beautiful fabrics
  • Use this block to imitate the dozens of patterns usually made with log cabin blocks (it’s the same basic visual design, just much simpler to make)
Half-square triangles are probably the most useful block a quilt designer can use. Get a pad of graph paper and some colored pencils and let your imagination soar. You’ll be surprised by the intricate designs you can make with one simple block. Have something to add? Leave a comment or connect with us on Facebook.
Make a comment
  • (will not be published)

34 Responses to “Tips for Half-Square Triangle Piecing”

  1. Ruthe Barnett

    I love working with half squares for my quilting projects. I find them very beautiful with a great sense of accomplishment when making blankets, and designs for hanging holiday completed projects. My family and friends are always complimenting me.

    Reply
  4. Pat Anderson

    Volunteer at the Shelburne Museum in VT and have been engaging children for the past 4 summers by offering them 4 or more half-square triangles to arrange. first changing my white square to a blue one, and then making a pinwheel. Then we look around to see what antique quilts also have half-square triangles. Much more fun for them than most museums!!!

    Reply
  5. carol garcia

    thank you for being so patient when you are asked repeatedly how to calculate the size square you need to cut to make a HST….that was exactly my question, to which i now know the answer, repeatedly….this is an amazing and rapid manner to make a bunch of HST, thanks againg…

    Reply
    • Christine

      Hi, I’m slow on math, so a 6″ finished block, the unfinished block is 6-1/2″, do we still cut the fabric with 6-7/8″ square? Also, when you put the block together, how to flat the join section? I love pinwheels but the center join section is kind of heavy, any tips helping to reduce it? Thanks for your help. Meanwhile, when you sew the 4 patches together, how to make a little 4 patch seams in the back? Thanks again.

      Reply
  6. Linda McCoy

    If your pattern calls for you to cut a 3 7/8 square to cut in half for the triangles then how much bigger do you cut the square to do the half square triangles your way?

    Reply
    • Customer Service

      The answer to this question is that it does not need to be cut any larger than the 3 7/8″ measurement given. Whether you cut the triangles in half then piece them back together or piece them first using two squares on top of each other then cut them in half as shown in the video, 7/8″ is the measurement that is ALWAYS added to the finished size of any square that is formed by two triangles which is often refered to as a “half square triangle unit”.
      Heather

      Reply
  7. Nancy

    I am ready to quilt my 1st star quilt have you any tips in the sandwich it together it is a double bed size and it will be quilted by machine heirloom wadding patterned back please can you help me thanks

    Reply
  9. Ricki Chichester

    I’m no expert quilter, but I can’t stand the thought of piecing fabric that has not been ironed. I see it all the time, but it really bothers me. Anyone else feel this way?

    Reply
  10. Jane Payn

    I upgraded my membership to premium, but I never seem to get anything different, and certainly shall not renew my membership if things don’t change.

    Reply
    • Customer Service

      Hi Jane,
      I have emailed you your login information with instructions on how to access your account so that you can view the Premium content.
      Please let me know if you did not receive the email.
      Sincerely,
      Kate

      NQC Video Membership

      Reply
      • Jane Martinez

        Sorry but I didn’t get your email so I can access my premium account. Can you resend please? Thanks

        Reply
        • Customer Service

          Hi Jane. I am sorry you are having trouble logging into your account. I have emailed you the login instructions. Please let me know if you do not receive the email. Thank you and Happy Quilting!

          Reply
  11. carol garcia

    ok, this is awesome, but how do i calculate the size i need?

    Reply
    • Customer Service

      Hi,

      This should answer both questions – for a half square triangle you add 7/8″ to the size you want the finished block to be. So, for a 6″ finished block you would start with a 6 7/8 ” square.

      Hope this helps!
      Cheers,
      Ashley

      Reply
      • Nancy

        I am new to quilting. If you want a finished square of 6 inches, you would cut a 6 1/2 inch square, sewing a 1/4 inch around the square. Am I missing something?

        Reply
        • Customer Service

          Hello Nancy,

          Yes, this is the case if you are sewing two squares together, however, when making half square triangles you add 7/8″. This means if you want a finished half square triangle of 1″ you make it from two 1 7/8″ squares following the method used in this article.
          Hope this helps!

          Cheers,

          Ashley
          National Quilters Circle Video Membership

          Reply
        • Tela

          It is because the beginning pieces are triangles and you are sewing on a diagonal when you sew across the middle of the squares. There is a free online app that will help you with it. And MSQC has a good book with lots of useful information.

          Reply
  12. Joanne

    Which way do you press the half-square triangle intersections on the quilt back for the flattest finish? Thank you.

    Reply
  13. Gwen DeSeure

    Seems ez-pz — so then why do my opened HST often seam a bit wonky & uneven. To square off makes them uneven placement of either fabric; i.e. dark proportion larger or vice versa.

    Reply
  14. Margaret

    What sized square do you need to get a finished 6inch square? Do you have to add on seven eights of an inch to start with?

    Reply
    • Customer Service

      Hi,

      For a half square triangle you add 7/8″ to the size you want the finished block to be. So, for a 6″ finished block you would start with a 6 7/8 ” square.

      Hope this helps!
      Cheers,
      Ashley

      Reply
  15. Colleen

    I was doing the 9 blocks in 9 weeks and couldn’t keep up with the ending of it and how to put the squares together and finishing the rest if it. Where can I get those instructions.

    Reply
    • Customer Service

      Hi Collen,

      Here is the link for the Final Recap:

      file:///C:/Users/kmcfarren/Downloads/Snowy-Day-Quilt-Sampler-Full-Pattern.pdf

      Please let me know if there is anything else you need!

      Reply
      • jacki cohoon

        I broke a few ribs in an accident and was unable to get to the end of the quilt instructions. I am trying to get back to finishing all I has started. I have the 9 blocks and need the instructions after that… this link does not appear to work for me. thank you for offering the quilt instructions… but could you please send the rest to me? thank you thank you

        Reply
        • Customer Service

          Hello Jacki,

          Please visit our Facebook page NQC Quilt Block Challenge. The instructions will be posted there.

          Thanks,
          Becky NQC Video Membership

          Reply
  18. Merlyn Kirk

    Lost pattern for snails trail after hubby passed away I moved (with a lot of help) can’t find many things this one is already started!

    Reply
    • Carolyn Thibodaux

      You might try Missouri Star Quilt Co. Jenny has a snail’s trail pattern which may help you; if not, maybe you can send a pic to see if she recognizes the pattern. Also, Jordan Fabrics may be able to help.

      Reply