Quilt Backing Calculator
Zero Waste & No Sign-up: Find the perfect backing for your quilt. Calculate yardage for standard 42-inch or wide-back 108-inch fabrics. Plan your seams to minimize waste. Ensure your backing has the ideal amount of overage for longarm quilting while optimizing your fabric layout for efficiency and durability.
How to Use the Backing Calculator
Enter the quilt top's width and height, the overhang you want on each side — 4 inches per side is the common longarm request — and your backing fabric width, whether standard 42 to 44 inch yardage or a 108-inch wide-back.
The calculator subtracts an inch from the stated fabric width for selvages, then prices both ways of piecing the back: panels joined with horizontal seams or with vertical seams. Each layout's yardage is the panel count times the needed dimension, plus a 10 percent waste allowance, rounded up to the next eighth of a yard — and the tool reports whichever direction needs less fabric, with its panel and seam count.
For a 60 x 80 inch top with 4-inch overhang the back must measure 68 x 88 inches; from 42-inch fabric that is two 88-inch panels and one seam, about 5-1/2 yards, instead of three panels the other way. Trim the selvages off every seamed edge and press the joining seam open before the backing is loaded on a frame or basted.
Frequently Asked Questions
Why does my backing need to be larger than the top?
Long-arm quilting machines require extra fabric on all sides to clamp the backing taut. Even for hand-quilting, the extra 'overage' prevents the backing from shifting too far and leaving gaps.
Should I seam my backing vertically or horizontally?
Vertical seams (running top to bottom) are generally more stable when hanging the quilt. Our tool calculates both options and suggests the one with less fabric waste.
Is 108-inch wide fabric better for backing?
For large quilts (Queen/King), wide-back fabric is excellent because it eliminates the need for piecing and seams, saving time and providing a smoother finish.