Quilting Tips: Setting Triangles

When you position quilt blocks on point (also called a diagonal set), you need to fill in the outer edges of the quilt with triangle-shaped cuts of fabric. Triangles along the side of the quilt are called side setting triangles. Corner setting triangles fit the corners of the quilt.

To calculate the size to cut the side setting triangles:

1. Multiply the finished size of your block by 1.414
2. Add 1 1/4″ to that number
3. Cut a square equal to the sum
4. Cut the square twice, corner to corner

Example for a 6″ block:

6″ x 1.414 = 8.484 (round up to 8 1/2″)

8 1/2″ + 1 1/4″ = 9 3/4″

Cut a square 9 3/4″ and cut it twice, corner to corner.

To calculate the size to cut corner setting triangles:

1. Divide the finished size of your block by 1.414
2. Add 7/8″ to that number.
3. Cut a square equal to the sum
4. Cut the square once, corner to corner

Example for a 6″ block:

6″ ÷ 1.414 = 4.24″ (round up to 4 1/4″)

4 1/4″ + 7/8″ = 5 1/8″

Cut a square 5 1/8″ and cut it once, corner to corner.

Happy Quilting,

The Tech Editors