A Backing for Quilts Calculator is a specialized textile and quilting tool used to determine the amount of fabric needed to back a quilt. It factors in the quilt’s width and length, extra inches for overhang and shrinkage, and the number of fabric panels necessary based on fabric width. Quilters rely on this tool to ensure they purchase the correct amount of fabric, eliminating the risk of shortage or excess. This calculator is essential for planning and budgeting, particularly for larger quilting projects that require multiple fabric panels or directional print considerations.
Detailed Explanations of the Calculator’s Working
This calculator functions by assessing your quilt dimensions (width and length in inches), adding allowance margins (typically 4–8 inches), and then determining the number of full-width panels needed. Each panel’s area is calculated, and the total area is converted from square inches to square yards. It assumes a standard fabric width (e.g., 42–44 inches) and can adapt to different widths if specified. This ensures that you’re not only accounting for quilt coverage but also fabric seam allowances and shrinkage after washing. The result gives you the total yardage required for your quilt backing.
Formula with Variables Description
Backing Fabric Required (yards) = ((Quilt Width (in) + Extra Width (in)) × (Quilt Length (in) + Extra Length (in)) ÷ 1296) × Number of Panels
- Quilt Width (in): The horizontal measurement of the quilt top
- Quilt Length (in): The vertical measurement of the quilt top
- Extra Width (in): Allowance for quilting and shrinkage, typically 4–8 inches
- Extra Length (in): Additional length allowance
- 1296: Conversion factor from square inches to square yards (36×36)
- Number of Panels: Total number of fabric widths needed to cover the quilt back
Quick Reference Table for Common Quilt Sizes
| Quilt Type | Standard Size (inches) | Backing Needed (yards) – 44″ Width | Panels |
|---|---|---|---|
| Baby Quilt | 36 x 52 | 1.75 | 1 |
| Throw Quilt | 50 x 65 | 2.75 | 2 |
| Twin Quilt | 65 x 88 | 5.25 | 2 |
| Full/Double Quilt | 80 x 88 | 5.75 | 2 |
| Queen Quilt | 90 x 100 | 6.75 | 3 |
| King Quilt | 110 x 108 | 8.75 | 3 |
Note: This table assumes an 8″ allowance and 44″ fabric width.
Example
Imagine you are backing a queen-size quilt that measures 90″ wide by 100″ long, and you are adding 8 inches of allowance for quilting. Assume your fabric is 44 inches wide, and you’ll need 3 panels to cover the width.
Backing Fabric Required (yards) = ((90 + 8) × (100 + 8) ÷ 1296) × 3
= (98 × 108 ÷ 1296) × 3
= (10584 ÷ 1296) × 3
= 8.17 × 3 = 24.5 yards
You’ll need approximately 8.17 yards per panel, totaling about 24.5 yards of 44″ wide backing fabric for a queen quilt.
Applications
Home Quilting Projects
Home quilters often work on gifts, heirloom projects, or personal throws. This calculator removes the trial-and-error process, making it easier to estimate fabric needs confidently and precisely.
Quilt Shops and Retail Planning
Fabric retailers can use this calculator to help customers determine how much backing fabric to purchase. It also assists in pre-cut fabric kits tailored to standard quilt sizes.
Professional Quilting Services
Longarm quilting services frequently require extra backing for loading the fabric onto machines. This calculator ensures clients bring in appropriately sized materials, streamlining workflow and reducing delays.
Most Common FAQs
Extra fabric (usually 4–8 inches) is needed to accommodate shrinkage, seam allowance, and to give quilting machines enough margin to hold and stitch the layers securely. This prevents the backing from running short during quilting, especially with longarm services.
If your fabric has a different width (e.g., 54″ or 60″), you must adjust the number of panels required. The calculator should be customized to reflect that width, which may reduce the number of panels or total yardage needed.
Yes, but additional adjustments may be necessary. For directional prints, fabric needs to be cut and joined in a way that maintains pattern orientation. This could require more yardage or different panel configurations.