Quilt Backing Calculator – Calculate Fabric for Quilt Backing
Calculate fabric needed for quilt backing with seam options
How to Use
- Enter your finished quilt width in inches
- Enter your finished quilt length in inches
- Specify seam allowance (usually 0.5 inches)
- Select backing style (single, horizontal, or vertical seam)
- Click calculate to see fabric dimensions and yardage needed
Understanding Quilt Backing
Quilt backing is the bottom layer of a quilt sandwich (backing, batting, and quilt top). It needs to be larger than the quilt top to allow for the quilting process, which can cause the fabric to shift and shrink slightly.
Standard quilting cotton is typically 42-45 inches wide after removing selvages. For quilts wider than this, you'll need to piece the backing with seams.
Backing Styles Explained
Single Width: Works for smaller quilts that fit within the fabric width. No seaming required.
Vertical Seam: Most common method. Fabric pieces run vertically (parallel to the quilt length). Efficient for bed quilts.
Horizontal Seam: Fabric pieces run horizontally (parallel to the quilt width). Good for directional prints or when you want the pattern to run a specific way.
Why Add Overhang?
Quilt backing should be 4-8 inches larger than the quilt top on all sides. This calculator uses 4 inches per side (8 inches total per dimension) to ensure:
- Adequate fabric for basting and pinning
- Room for the quilt to shift during quilting
- Compensation for fabric shrinkage during quilting
- Easier handling on longarm or domestic machines
- Professional finishing without running short of fabric
Fabric Selection Tips
- Choose 100% cotton quilting fabric for best results
- Prewash your backing fabric to prevent shrinkage
- Consider using wide backing fabric (108 inches) to avoid seams
- Match the fiber content of backing to your quilt top
- For directional prints, plan seam placement carefully
- Buy an extra 1/2 yard as safety margin for large quilts
Frequently Asked Questions
- How much bigger should quilt backing be than the quilt top?
- Quilt backing should be 4-8 inches larger than the quilt top on all sides. This calculator uses 4 inches per side (8 inches total width and length) to provide adequate overhang for the quilting process.
- What's the difference between vertical and horizontal seam backing?
- Vertical seam backing has fabric pieces running parallel to the quilt length, while horizontal seam backing runs parallel to the width. Vertical seams are more common and efficient for most bed quilts, but horizontal seams work better for certain directional prints.
- Can I use wide backing fabric to avoid seams?
- Yes! Wide backing fabric (typically 108 inches wide) eliminates the need for seams on most quilts. While more expensive per yard, it saves time and creates a seamless backing. This calculator assumes standard 42-inch fabric width.
- Do I need to prewash quilt backing fabric?
- It's recommended to prewash backing fabric, especially if you plan to wash the finished quilt. Prewashing prevents shrinkage and color bleeding. Wash in the same way you'll care for the finished quilt, then press before cutting.