Enter your quilt dimensions, backing fabric width, and seam allowance to find out exactly how much fabric and batting you need. The Quilt Calculator returns the total yardage for backing, batting size, and number of fabric panels required — no mental gymnastics needed.
Backing Fabric Needed
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Number of Backing Panels
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Total Backing Width Needed
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Total Backing Length Needed
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Batting Width Needed
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Batting Length Needed
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Backing Yardage (Rounded Up to 1/8 yd)
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Most quilters add 2–4 inches on each side of the quilt top for backing, giving 4–8 inches total extra width and length. This overhang is needed for the quilting frame or longarm machine to grip the fabric. A standard choice is 4 inches per side (8 inches total).
WOF stands for Width of Fabric — the usable width of the fabric bolt after selvages are trimmed. Most quilting cotton is about 40–44 inches wide after washing. Wider backing fabrics (60" or 108") can reduce or eliminate the need for seaming panels together, saving both fabric and time.
The number of panels depends on your quilt width plus overhang compared to the usable fabric width. If one panel isn't wide enough, a second (or third) panel is sewn lengthwise. The calculator determines the minimum number of panels needed and totals the yardage required.
Yes. When multiple panels are needed, the calculator subtracts the seam allowance (e.g. 1/2 inch) from each seam join when computing usable panel width, so your final yardage figure accounts for fabric lost in the seam.
Many quilters prewash their backing fabric to pre-shrink it and remove any sizing or chemicals. If you prewash, subtract about 2–3% from the WOF (usable width) to account for shrinkage, or simply purchase an extra 10% of yardage as a safety buffer.
Batting typically extends 1–2 inches beyond the quilt top on each side (less than backing), because it doesn't need to wrap around a frame. Backing needs more overhang — usually 2–4 inches per side — to allow for clamping or pinning during the quilting process.
Absolutely. Simply enter your king-size quilt dimensions (commonly around 108" × 96") and select a wide backing fabric such as 108" extra-wide fabric. With 108" fabric, you may need only one panel, significantly reducing yardage waste and eliminating a center seam.
Fabric is typically sold in increments of 1/8 yard at most quilt shops. Rounding up to the nearest 1/8 yard ensures you purchase enough without waste, and matches the quantities a store cashier would cut at the fabric counter.