how to calculate backing for quilts

3 min read 16-01-2025

Quilting is a rewarding hobby, but accurate fabric calculations are crucial for a successful project. Getting the backing right is key – too little, and you'll have a frustrating piecing project; too much, and you'll waste valuable fabric. This guide will walk you through how to calculate backing for quilts of all sizes, ensuring your next quilting project goes smoothly.

Understanding Quilt Backing Requirements

Before diving into calculations, understand that quilt backing needs extra fabric for several reasons:

Seam Allowance: You'll need extra fabric to accommodate seam allowances when joining backing pieces.
Shrinkage: Pre-washing fabric is highly recommended to prevent shrinkage after the quilt is finished. This step necessitates adding extra fabric.
Pattern Matching (Optional): Some quilters prefer to match patterns on their backing. This requires additional fabric to achieve a seamless look.

Methods for Calculating Quilt Backing

There are several approaches to calculate the backing fabric, each with varying levels of precision.

Method 1: The Simple Method (Best for Beginners)

This method adds a generous amount of extra fabric to account for seam allowances and potential shrinkage. It's perfect for beginners or quick projects.

Measure your quilt top: Determine the width and length of your finished quilt top.
Add 6-8 inches to both width and length: This extra fabric accounts for seam allowances and shrinkage.
Check for multiple pieces: If your quilt requires multiple backing pieces, divide the calculated total by the width of your fabric to determine the number of pieces needed.

Example:

A quilt top measures 60" x 80".

60" + 6" = 66"
80" + 6" = 86"

You'll need backing fabric measuring at least 66" x 86".

Method 2: The Precise Method (For Advanced Quilters)

This approach provides a more accurate calculation by precisely factoring seam allowances and shrinkage.

Measure quilt top: Determine the exact width and length of your finished quilt top.
Add seam allowance: Add twice the seam allowance (usually ½ inch or 5/8 inch) to both width and length.
Account for shrinkage: Add 4-6% to both width and length to compensate for shrinkage (pre-washing helps minimize this).
Check for multiple pieces: Calculate the number of backing pieces needed based on the calculated dimensions and fabric width.

Example: Using a 60" x 80" quilt top with a ½-inch seam allowance:

Width: 60" + 2(0.5") = 61"
Length: 80" + 2(0.5") = 81"
Shrinkage (5%):
- Width: 61" * 0.05 = 3.05" => 61" + 3.05" = 64.05" (Round up to 64.5")
- Length: 81" * 0.05 = 4.05" => 81" + 4.05" = 85.05" (Round up to 85.5")

You'll need backing fabric measuring approximately 65" x 86".

Method 3: The Pattern Matching Method (For Specific Designs)

If you want to match a pattern on your backing, follow these steps:

Measure quilt top: Determine width and length.
Calculate repeat: Measure the repeat of your fabric pattern (the distance before the pattern repeats).
Determine pieces: Calculate how many repeats you need to cover the width and length, ensuring seamless pattern matching.
Add seam allowance and shrinkage: Account for seam allowance and shrinkage as described in Method 2.

Important Note: This method usually requires significantly more fabric than the previous methods.

Frequently Asked Questions (FAQs)

Q: What type of fabric is best for quilt backing?

A: Consider fabrics like cotton, flannel, or linen, depending on your preference and the quilt's weight. Choose a fabric that is a similar weight and drape to your quilt top. Learn more about choosing the best quilt backing fabric.

Q: Should I pre-wash my backing fabric?

A: Yes! Pre-washing your backing fabric is highly recommended to prevent shrinkage and ensure the final product maintains its size and shape.

Q: What if my backing fabric is not wide enough?

A: You will need to piece your backing fabric together using a seam allowance. This is perfectly acceptable, and the seams will be hidden when the quilt is quilted.

Conclusion

Calculating backing for quilts might seem daunting, but with these methods, it becomes manageable. Choose the method that best suits your skill level and project requirements. Remember, accurate calculations save you fabric and frustration, ultimately leading to a beautifully finished quilt. Remember to always double-check your measurements and account for seam allowances and shrinkage to ensure a successful project. Happy quilting!