Sewing & Quilting Quilt Backing Calculator
Created by: Sophia Bennett
Last updated:
Plan quilt backing dimensions, panel joins, and yardage with overhang and shrinkage allowances for standard and wide-back fabric.
Quilt Backing Calculator
SewingEstimate backing size, panel count, and yardage for quilting
Quilt and Backing Inputs
Related Calculators
What is a Quilt Backing Calculator?
A quilt backing calculator estimates backing dimensions, number of panels, and fabric yardage based on your quilt size, extra overhang, and backing fabric width.
It helps avoid undersized backing and supports accurate shopping for standard width or wide-back fabric.
Quilt Backing Formulas
Required Backing Width: Quilt Width + (2 × Overhang)
Required Backing Length: Quilt Length + (2 × Overhang)
Usable Panel Width: Fabric Width − Seam Allowance
Panel Count: ceil(Required Backing Width ÷ Usable Panel Width)
Total Yardage: (Panel Count × Required Backing Length × Shrinkage Factor) ÷ 36
Example Calculation
For a 60 by 80 inch quilt with 4 inch overhang and 44 inch backing fabric:
- Required backing size = 68 by 88 inches
- Panel count depends on usable panel width after seam allowance
- Yardage includes optional shrinkage percentage
Common Applications
- Longarm prep: Ensure backing extends enough for loading clamps
- Domestic quilting: Plan panel joins and reduce handling issues
- Wide-back planning: Compare 44 inch and 108 inch options
- Fabric shopping: Estimate realistic purchase yardage quickly
Tips for Backing Success
- Square backing fabric before panel joins
- Press seams open to reduce bulk on the longarm
- Check grain direction before cutting long backing panels
- Round yardage up for directional or large-scale prints
Frequently Asked Questions
How much larger should quilt backing be?
A common longarm standard is 4 inches extra on each side, which means 8 inches added to both width and length.
Do I need to piece backing fabric?
If required backing width is larger than your fabric width, yes. This calculator estimates panel count and joined width.
What is wide backing fabric?
Wide backing is often 108 inches, which can avoid seams for many quilts and simplify preparation.
Should I include shrinkage?
Yes. If you prewash, include shrinkage to avoid ending up short after laundering and pressing.
Does seam allowance reduce panel width?
Yes. Joined panels lose usable width at each seam, so seam allowance must be considered in panel calculations.
Can I use this for directional prints?
Yes, but directional matching may require extra length beyond standard estimates.
Should I buy exact yardage?
It is safer to round up to the nearest quarter yard for cutting tolerance and alignment adjustments.
Sources and References
- Longarm Quilting Fundamentals, backing preparation guidelines
- The Quilters Bible, backing and finishing chapters
- American Quilter Society educational recommendations