Add at least twice the border width to the border lengths instructed to cut.

Center and sew the side borders to the quilt, beginning and ending stitching 1/4" from the quilt corner and backstitching (Figure 1). Repeat with the top and bottom borders.
Mitered Borders
Fold and pin quilt right sides together at a 45-degree angle on one corner (Figure 2). Place a straightedge along the fold and lightly mark a line across the border ends.
Mitered Borders
Stitch along the line, backstitching to secure. Trim seam to 1/4" and press open (Figure 3).
Mitered Borders