Mitered quilt borders aren't quite as common as butted quilt borders, which are often called straight borders. In part, many people believe that mitered quilt borders are more difficult to sew.
- Mitered quilt borders are attached to each other with a 45-degree diagonal seam where the borders meet at corners of the quilt, like the example above left.
- Straight quilt borders butt into each other where they meet at quilt corners, like the example above right.
Mitered borders require that you use setting in techniques to sew them to the quilt, but the setting in isn't difficult once you've experimented with the method.
Why Should You Use Mitered Borders in a Quilt?
Some quilters prefer the appearance of mitered borders.
Mitered borders make it possible to create a kaleidoscope look where they meet at corners of a quilt, a technique that's often used when working with border prints. Take a look at 'Hunter's Star Quilt Pattern' for an example. To create something similar, cut each border intersection so that it meets at an identical part of a print when seams are sewn.
The technique is easier for square quilts since all borders are the same length and naturally end in the same area of fabric. But borders for rectangular quilts create the same effect.
The same method works perfectly to match up stripes where the miters meet.
Sewing Multiple Mitered Borders to a Quilt
If you use multiple mitered borders, sew all of the strips for each side together lengthwise.
Borders are easier to match at mitered corners when you press seam allowances between the strips in the side borders in the opposite direction as the seam allowances in top and bottom borders. Seam allowances where borders connect will butt into each other for a perfect match.
Sew each multi-border unit to the quilt in one piece, stopping 1/4" from each end and leaving the mitered ends uncut and unsewn until all borders are in place.
Mitered Borders Require Extra Length
You will need to add extra length to sew mitered borders, but the amount depends on the mitering technique you use. The pattern linked above can help, but there are many other methods for mitering borders.
The grouped borders may be fine if cut to different lengths, with the innermost border shorter and lengths increasing as more are added (because the quilt's dimensions increase as more width is added to borders). It is easier to just allow the amount extra needed overall and cut—or piece—strips of the same length before sewing them together.
One common formula for mitered border length is:
Quilt side dimension + 2 times the width of all borders + 6"
When quilt borders are measured and sewn accurately they offer a way to square up a quilt top that's a little skewed. We sometimes forget about that when sewing mitered borders. The extra length at each end of the strips makes it easy to just sew the borders in place without regard to their correct placement.
You should always be aware of the correct midpoints and endpoints for each border. Measure your quilt as described in our straight border instructions and apply the borders in a similar way to square up skewed areas that might exist.