We love the half-square triangle method Amy Smart references in her Hopscotch Quilt Pattern, and are so happy to bring you a video tutorial! Learn to make 16 half square triangle pairs in no time at all. Use this method with the December Pattern Drop Quilt, and all of your other half square triangle projects!

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To Make 16 Half Square Triangle Pairs

Step 1: Cut two 10”x20” pieces of fabric (in this case, one white and one tan).

  • Place the two pieces of fabric right sides together and pin

Step 2: Mark a 4 x 2 grid as shown

  • Mark lines 5 inches apart, as shown.

Step 3: Mark the diagonal lines as shown, making two diamonds

Step 4: Using the diamonds as your guide, sew a ¼” seam on both sides of the lines. The fastest way to sew these is to sew two ‘figure 8’ zig-zags. Take a look at the illustrations below to see how the figure 8’s work.

  • Begin sewing on the ends of the fabric (green dot)
  • Tips on how to make the turns:
    • When you are sewing inside of the diamonds:
      • Stop the needle in the down position on the gridlines (red dots)
      • Then lift the presser foot, rotate the fabric, lower the presser foot, and continue sewing.
    • When you are sewing the outside of the diamonds:
      • Sew off of the fabric and simply re-align with the next line (purple dots) and continue sewing.

This is the first ‘figure 8,’ zig-zag path that you’ll sew

This is the second ‘figure 8,’ zig-zag path that you’ll sew

Step 5: Use a rotary cutter to cut the fabric into 5”x5” squares

  • Cut along the vertical and horizontal lines that you marked in Step 2

Step 6: Use a rotary cutter to cut the squares into triangles

  • Cut along diagonal lines that run from corner to corner
  • Be sure that you are cutting between the two seams


Step 7: Use the Quilt in a Day Half Square Triangle ruler to square up the sides

  • Leave the triangles as they are (don’t unfold them yet)–you can give them a quick press to set the seam, if you want.
  • Line up the appropriate dotted line with the seam of the triangle. The size indicated on the ruler is the size of the finished HST.
    • Note: for the Hopscotch Quilt use the 4 ½ size
  • Use a rotary cutter to trim both exposed edges of the triangle
  • Amy’s Tip: you don’t need to worry about centering the ruler perfectly. As long as the dotted line is over the seam it will square up the edges perfectly

If you’d like to get the Quilt in a Day ruler, Click Here to buy it on Amazon

Step 8: Press the seam open

  • Be sure to press the seam towards the darker fabric. If you press it towards light-colored fabric, the darker fabric may show through and be visible

Here are all of the tools used in this tutorial and video:

Similar cutting mats:


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