How to calculate quilt borders
Cut width = finished width + 1/2"
Butted corners: sides = quilt length; top and bottom = quilt width + 2 × border width
Mitered corners: each strip = side + 2 × border width + 4"
Strips = total length ÷ 40", rounded up
Measure the quilt center through the middle, raw edge to raw edge. Borders are sewn on in order: border 1 goes on the quilt center, border 2 on border 1, and so on. Each border makes the next one longer.
Worked example: two borders on a 40" × 50" center
A 2" inner border and a 5" outer border, butted corners, cut across 40" usable fabric:
- Border 1: cut 2 1/2" strips. Sides 50", top and bottom 44" (40 + 2 × 2). Total 188", so 5 strips: 3/8 yard.
- Border 2: cut 5 1/2" strips. Sides 54", top and bottom 54" (44 + 2 × 5). Total 216", so 6 strips: 1 yard.
- Finished quilt: 54" × 64".
Butted or mitered corners?
- Butted (straight) corners are quicker and use less fabric. Sew the sides first, then the top and bottom.
- Mitered corners give a picture-frame look and suit striped or directional border prints. Each strip needs extra length for the 45° seam.
Avoiding wavy borders
- Measure through the center, not the edges.
- Cut borders to that measurement, then pin the middle and ends before easing in the rest.
- Sew with the border on the bottom so the feed dogs ease in any fullness.