How to Calculate Quilt Binding

What Is Quilt Binding and Why Does Calculation Matter?

Quilt binding is the strip of fabric that wraps around the raw edges of your finished quilt sandwich (top, batting, and backing). It protects the edges from fraying and gives the quilt a clean, finished appearance. Getting the calculation right means you will not run out of binding mid-quilt or buy far more fabric than needed.

Binding is typically cut into strips 2.25–2.75 inches wide, folded in half lengthwise, and stitched to both sides of the quilt edge. A 2.5-inch strip is the most common choice and works well for standard quilt thickness.

The Basic Binding Formula

Follow these four steps to calculate any binding project:

Step 1: Calculate the Perimeter

Add together all four sides of your quilt:

For example, a queen quilt measuring 90″ × 108″ has a perimeter of (2 × 90) + (2 × 108) = 180 + 216 = 396 inches.

Step 2: Add Extra for Corners and Joining

Always add 10–12 inches to account for the diagonal joins when connecting strips and for the extra needed at each corner. Most quilters use 12 inches as a safe buffer:

For the queen example: 396 + 12 = 408 inches of binding needed.

Step 3: Calculate the Number of Strips

Divide your total binding length by the usable width of your fabric. Standard quilting cotton is about 40–42 inches wide after trimming selvages. Use 40 inches to be safe:

For the queen example: 408 ÷ 40 = 10.2, so you need 11 strips (always round up).

Step 4: Calculate Yardage

Multiply the number of strips by the strip width (typically 2.5 inches), then divide by 36 to convert to yards:

For the queen example: (11 × 2.5) ÷ 36 = 27.5 ÷ 36 = 0.76 yards — buy at least 1 yard for comfort.

Regular vs. Bias Binding: What Changes?

The formula above calculates regular (straight-grain) binding, which is cut parallel to the selvage. Regular binding is the most common choice and works perfectly for quilts with straight edges.

Bias binding is cut at a 45° angle to the selvage. Because of the diagonal cut, you lose more fabric to waste. To calculate bias binding yardage, multiply your regular binding yardage by 1.414 (the square root of 2):

Bias binding is best for quilts with curved edges — the diagonal grain gives it stretch to curve smoothly without puckering. It is also generally more durable because wear is distributed across the diagonal threads rather than concentrated on one grain line.

How Strip Width Affects Total Yardage

Binding strip width is one of the most important variables. Here is how common widths compare for a queen quilt:

A wider strip gives more fabric to wrap around thicker quilt edges. If your quilt has especially thick batting or is a rag quilt, consider a 2.75″ or 3″ strip.

Common Mistakes When Calculating Binding

• 1.Using the full fabric width: Selvages must be trimmed. Always use 40″ as your working width, not 44″.
• 2.Forgetting the joining allowance: Each diagonal seam joining two strips uses about 3–5 inches of fabric. Add 12″ minimum to your perimeter.
• 3.Rounding strips down instead of up: If your calculation gives you 10.2 strips, cut 11. You cannot sew half a strip.
• 4.Forgetting pre-wash shrinkage: If you pre-wash your fabric, account for 3–5% shrinkage. Buy an extra ¼ yard on projects using pre-washed fabric.
• 5.Not adding enough for bias binding: The 1.414 multiplier is essential — skipping it leaves you significantly short on fabric.

Quick Reference: Binding for Common Quilt Sizes

Want to design a multi-color or scrappy binding? See the Pieced Binding Planner to calculate fabric per color and visualize the layout.