You can sew two individual triangles together to create a half square triangle unit, but there are quick piecing methods that help you make them much more quickly, and without handling the stretchy bias edges of individual triangles.
This quick piecing method is a good choice whenever you're making a scrap quilt or need a few units in specific color combinations. It's my favorite method, so I use it even when I'm making lots of duplicates.
To make half-square triangle units, you'll sew two squares of fabric together, and then cut them apart to create two identical triangle units. Use the square size called for in your pattern. If you are drafting your own pattern, cut squares that are 7/8" larger than the finished size of the triangle square.
Mark & Sew the Squares
- Use a pencil or permanent marker to draw a diagonal line (from one corner to the opposite corner) on the reverse side of the lightest square.
- Pair the marked square with the same size darker square, edges matched and right sides together.
- Sew two seams, each one 1/4" from the marked center line. Measure and draw seam lines before sewing if you do not have a 1/4" presser foot to guide you.


