Quilt Binding Calculator
Enter your quilt dimensions to find out how many binding strips you need and how much fabric to buy.
Tip: use URL parameters to pre-fill, e.g. ?quiltWidth=72&quiltLength=90.
How the quilt binding calculation works
Binding is the fabric strip that finishes the raw edges of your quilt. The amount you need depends on the perimeter of the quilt plus a little extra for joining the strips and turning the corners.
Step 1: find the perimeter. Add the width and length, then double it. A 60" × 80" quilt has a perimeter of 2 × (60 + 80) = 280 inches.
Step 2: add joining allowance. You need extra for the diagonal seams where strips meet and for the folded miters at corners. A common rule of thumb is to add 10–12 inches for an average lap quilt. This calculator uses 12 inches.
Step 3: split into strips. Binding strips are usually cut across the width of the fabric (WOF). Divide the total binding length by your usable fabric width and round up. For a 42" usable width, 292 inches of binding means 292 ÷ 42 ≈ 7 strips.
Step 4: convert to yardage. Multiply the number of strips by the cut width of each strip, then divide by 36. Seven strips at 2.25" wide is 7 × 2.25 = 15.75 inches of fabric, or about 0.44 yards — in practice you'd buy a fat quarter or ½ yard.
This calculator assumes straight-grain binding cut across the width of the fabric. For bias binding, use a wider estimate because strips are cut on the diagonal from a square of fabric.
What each input means
- Quilt width and length (inches) — the finished dimensions of the quilt top you're binding, measured edge to edge. If your top has borders, measure the full outer size, not just the block area.
- Binding width (cut width) — how wide you cut each strip before folding. This is not the finished binding width: a 2.25" cut strip folds to roughly 3/8" finished. Most patterns use 2.25" to 2.5".
- Fabric width (usable) — the width of fabric you can actually cut across after removing the selvedges. Quilting cotton is sold 44"–45" wide, but the usable width is usually about 42", which is what this calculator assumes.
Common mistakes to avoid
- Entering the finished binding width instead of the cut width. If you want 1/4" finished binding, you don't cut 1/4" strips — you cut roughly 2.25" and fold.
- Skipping the joining allowance. The 12 inches this calculator adds covers diagonal seams and corner folds. Without it, you'll run out during the final join.
- Using the full 44" fabric width. Selvedges are unusable; a 44" cut can rarely produce a true 44" strip. Using ~42" keeps your estimate honest.
- Buying the exact calculated yardage. Fabric is sold in fixed cuts, so round up to the nearest 1/8 or 1/4 yard. It's far better to have a few inches left over.
- Ignoring directional prints. Stripes and one-way designs can require matching or longer cuts, which adds 10–20% on top of this estimate.
Frequently asked questions
How wide should quilt binding strips be cut?
For most quilts, 2.25" to 2.5" cut width produces a finished binding of about 3/8" to 1/2". This calculator defaults to 2.25". If you prefer a wider or tighter finish, change the binding width input.
Straight-grain or bias binding — which do I need?
Straight-grain binding is simpler and works well for quilts with straight edges. Bias binding is cut on the diagonal, so it stretches and wraps curved edges more easily. For a rectangular quilt, straight-grain is usually fine.
Why do I need extra fabric beyond the perimeter?
Strips are joined with diagonal seams, each of which consumes a little length, and each corner needs extra fabric to fold into a miter. Without the allowance, you'll come up short at the final join.
What if my fabric has a pattern that needs matching?
Add 10–20% to the final yardage if you need to match a directional print or fussy-cut the binding. This calculator gives a plain-fabric estimate.