Formula
Butted sides equal the quilt’s length at the moment that border is sewn. Top and bottom equal the width plus two finished border widths. The top grows by two border widths before the next border is cut, so a second border is longer than the first.
butted length = 2 × length + 2 × (width + 2 × border)
mitered strip = side + 2 × border + extra
cut width = border + ½ in
strips = ceil(total length ÷ fabric width)
yards = strips × cut width ÷ 36, up to ⅛ yd
The ½ inch on the cut width is two ¼ inch seam allowances. The miter extra defaults to 2 inches per strip.
Worked examples
60 × 80, one 3 in butted border, 42 in goods. Sides are 80 in. Ends are 66 in. Total strip is 292 in, which is 7 strips. Cut width is 3.5 in, so the cloth is 24.5 in, or 0.75 yard after the eighth-yard round-up.
The same top, mitered, 2 in extra. Each side strip is 80 + 6 + 2 = 88 in and each end strip is 60 + 6 + 2 = 68 in. Four of those is 312 in.
Two 2.5 in butted borders on an 88 × 104 top. The first border is cut from 88 × 104. The second is cut from the larger top, 93 × 109, because the first border is already on.
Reference
One butted border on a 60 × 80 inch top, 42 inch usable goods, ¼ inch seams.
| Border | Strip length | Strips | Cut width | Buy |
|---|---|---|---|---|
| 2 in | 288 in | 7 | 2.5 in | 1/2 yd |
| 2.5 in | 290 in | 7 | 3 in | 5/8 yd |
| 3 in | 292 in | 7 | 3.5 in | 3/4 yd |
| 4 in | 296 in | 8 | 4.5 in | 1 yd |
| 5 in | 300 in | 8 | 5.5 in | 1 1/4 yd |
Questions
How long is a butted border strip?
Side strips match the quilt’s current length. Top and bottom strips are the width plus two finished border widths, so they cover the ends of the side strips. A 60 by 80 quilt with a 3 inch border needs 2 × 80 + 2 × 66 = 292 inches of strip.
What changes with a miter?
Each of the four strips is the side it covers plus two border widths plus an extra for the miter. The extra on this page starts at 2 inches. That extra is a sewing allowance, not a code or a published standard.
How is the cut width figured?
Cut width is the finished border plus 1/2 inch, which is two 1/4 inch seam allowances. Strips are the total length divided by the usable fabric width, rounded up. Yardage is strips times cut width, divided by 36, then up to the next 1/8 yard.
Sources
- Butted: sides = current length; top and bottom = width + 2 × finished border. Each border is added before the next is measured.
- Mitered: each strip = side + 2 × border + extra. Extra defaults to 2 in. Cut width = border + ½ in for two ¼ in seams. Yardage rounds up to ⅛ yd.