Which quilt measurements should I enter?
Enter the actual unfinished top edge size, or select projected finished seam-line dimensions. Finished input adds two project seam allowances to recover the raw top; raw input is not increased. The backing target is that raw rectangle plus your chosen overhang on all four sides. A border planner link carries its resulting raw top automatically. After quilting or washing, remeasure rather than assume the predicted size.
Use the fabric width available after removing selvages, not the label on the bolt. The example margin is editable: your quilting setup or longarm quilter may need different overhang and seam allowances. Fabric shrinkage, defects and pattern-repeat matching need separate allowances.
Panel count and yardage formula
Backing target = raw top + 2 × overhang, in each dimension Joined width of N panels = N × usable WOF − 2 × seam × (N − 1) Choose the smallest whole N that covers the target span Exact bolt length = N × required panel length Purchase length = round total bolt length UP once to your increment
Each seam consumes one seam allowance on each of its two fabric edges. For vertical seams, panel length runs top to bottom; horizontal seams require the quilt to turn relative to the fabric. The comparison uses straight rectangular panels with no lengthwise patching. It can deliberately use more fabric than a scrap-insert or diagonal method. The cut list includes actual panel widths and lengths, rather than only an area estimate.
Worked example: 60 × 80-inch top
With 4 inches beyond every side, the target is 68 × 88 inches. A usable width of 42 inches and ½-inch seams per edge gives two joined panels 42 + 42 − 1 = 83 inches of capacity. For vertical seams, cut two 88-inch lengths: 176 inches along the bolt, or 4.8889 yards. Rounding the aggregate once to ⅛-yard increments means buying 5 yards.
Turning the layout makes the required joined span 88 inches. Two panels only reach 83, so three 68-inch lengths are needed: 204 inches, or 5.6667 yards, rounded to 5¾ yards. This is why a rotation comparison matters. If the print must stay upright with bolt length down the quilt, choose that restriction and the other orientation is excluded.
Seam placement and honest offcuts
Balanced panels distribute the required cut width evenly. Full-width-first panels retain the full usable width until the final narrower panel. Both consume the same number of bolt lengths in this model. For the 68-inch span above, balanced cuts are 34½ inches each, joining to 68 inches; full-width-first cuts are 42 and 27 inches. Seams and dimensions in the diagram follow that choice. A two-panel balanced layout still has a central seam; it is not a promise to avoid one.
The result lists side offcuts, seam consumption and the extra bolt length caused by purchase rounding separately. Do not assume trimmed pieces have disappeared or that they can be reused for another panel without extra seams. All panels retain the same nap direction; reversal and repeat matching are excluded.
Before buying or cutting
Ask your quilter about margins, seam pressing and preferred seam direction. Confirm actual usable width after any prewashing. These are dimensioned planning diagrams, not full-size patterns or a physical-fit guarantee. For published preparation advice, see the Handi Quilter reference manual. Quilter's Paradise illustrates the same importance of turning a quilt when estimating backing; our equations and worked example are independently derived.