Calculate Backing for Quilt

Quilt Backing Yardage Calculator

Calculation Results

Total Backing Width Needed: inches

Total Backing Length Needed: inches

Number of Panels Required:

Total Yardage: yards

(Rounded up to the nearest 1/8 yard)

function calculateQuiltBacking() { var width = parseFloat(document.getElementById('quiltWidth').value); var length = parseFloat(document.getElementById('quiltLength').value); var fWidth = parseFloat(document.getElementById('fabricWidth').value); var overhang = parseFloat(document.getElementById('overhang').value); if (!width || !length || !fWidth || isNaN(overhang)) { alert("Please enter valid dimensions for all fields."); return; } // Total dimensions needed including the extra margin on all sides var neededWidth = width + (overhang * 2); var neededLength = length + (overhang * 2); // Calculation Logic 1: Seams running parallel to the length (Vertical) // Number of panels needed to cover the width var panels = Math.ceil(neededWidth / fWidth); // Total inches of fabric needed var totalInches = panels * neededLength; // Convert to yards var rawYards = totalInches / 36; // Round to nearest 1/8 yard (0.125) var finalYards = Math.ceil(rawYards * 8) / 8; document.getElementById('resTotalWidth').innerText = neededWidth; document.getElementById('resTotalLength').innerText = neededLength; document.getElementById('resPanels').innerText = panels; document.getElementById('resYards').innerText = finalYards.toFixed(3); document.getElementById('backingResult').style.display = 'block'; }

How to Calculate Backing for Your Quilt

Choosing and measuring the backing for a quilt is one of the most critical steps in the finishing process. Unlike the quilt top, the backing must be significantly larger to accommodate the quilting process, especially if you are sending your project to a longarm quilter.

The 4-Inch Rule

In the quilting world, the "4-inch rule" is the gold standard. This means you should add at least 4 inches of extra fabric to every side of your quilt top. If your quilt is 60″ x 70″, your backing should measure at least 68″ x 78″. This extra margin allows the longarm machine to grip the fabric properly and accounts for any shifting or shrinkage that occurs during the quilting process.

Standard Width vs. Wide-Back Fabric

Most quilting cotton comes in a 42″ to 44″ width. If your quilt is wider than approximately 34″ (after adding margins), you will need to piece together multiple panels of fabric to create a backing. Alternatively, "Wide-Back" fabrics are available in 108″ widths, which often allow you to have a seamless backing for even large King-sized quilts.

Example Yardage Calculation

Let's say you have a Throw Quilt that is 50 inches wide by 60 inches long and you are using standard 42-inch fabric:

• Step 1: Add 8 inches to both dimensions (4″ per side). Needed size: 58″ x 68″.
• Step 2: Determine panels. 58″ divided by 42″ fabric = 1.38, which rounds up to 2 panels.
• Step 3: Calculate length. 2 panels × 68 inches = 136 inches total.
• Step 4: Convert to yards. 136 / 36 = 3.78 yards.
• Final Buy: You would likely purchase 3.875 (3 7/8) or 4 yards to be safe.

Expert Tips for Quilt Backing

• Remove Selvages: Always cut off the selvages before sewing backing panels together, as the selvage is woven more tightly and can cause puckering.
• Directional Prints: If your backing fabric has a directional pattern, you may need to buy extra yardage to ensure the pattern flows the same way across all panels.
• Seam Allowance: Use a 1/2 inch seam allowance for backing seams and press them open to reduce bulk for the quilter.
• Square It Up: Before handing your quilt over to a professional, ensure your backing is squared so it loads onto the frame evenly.