How to Calculate Quilt Binding
Quilt binding finishes the raw edges of your quilt. The basic formula is: measure the quilt perimeter (2 x width + 2 x height), add 12 inches for corners and joining strips, then divide by your fabric width to find how many strips to cut. Multiply the number of strips by the strip width to get total fabric needed.
Binding Width Guide
| Cut Width | Finished Edge | Best For |
|---|---|---|
| 2" | ~1/4" | Miniature quilts, wall hangings |
| 2.25" | ~5/16" | Thin batting, art quilts |
| 2.5" | ~3/8" | Standard — works for most quilts |
| 2.75" | ~7/16" | Thicker batting, flannel quilts |
| 3" | ~1/2" | Extra-thick batting, heavy quilts |
Straight Grain vs Bias Binding
| Feature | Straight Grain | Bias |
|---|---|---|
| Cut direction | Parallel to selvedge | 45-degree angle |
| Stretch | Minimal | Good stretch on curves |
| Best for | Straight-edge quilts | Curved edges, scallops |
| Fabric needed | Less (standard calc) | 25-30% more than straight |
| Durability | Good | Excellent — wears evenly |
| Difficulty | Beginner-friendly | Intermediate |
Binding Fabric by Quilt Size
| Quilt Size | Perimeter | Strips (42" fabric) | Fabric (2.5" strips) |
|---|---|---|---|
| Crib (36"x54") | 180" | 5 | 3/8 yd |
| Twin (70"x90") | 320" | 8 | 5/8 yd |
| Full (85"x90") | 350" | 9 | 5/8 yd |
| Queen (90"x95") | 370" | 10 | 3/4 yd |
| King (108"x95") | 406" | 10 | 3/4 yd |
FAQ
Why add 12 inches to the binding length?
The extra 12 inches accounts for mitered corners (about 1 inch per corner = 4 inches), overlapping the start and end of the binding strip (6-8 inches), and a small margin for error. Some quilters add up to 18 inches for extra safety.
Can I use fat quarters for binding?
Yes, but only for small quilts. A fat quarter (18"x22") yields about 7 strips at 2.5" wide, giving you roughly 154 inches of binding. That is enough for quilts up to about 60 inches in perimeter — small wall hangings or table runners.
How do I join binding strips?
Join strips at a 45-degree angle (diagonal seam). Place two strips right sides together at a perpendicular angle, sew diagonally from corner to corner, trim the seam to 1/4 inch, and press open. Diagonal seams distribute bulk and are less visible than straight seams.
Related Tools
- Quilt Size Calculator — dimensions, blocks, and fabric for any quilt
- Bias Tape Calculator — fabric for bias binding strips
- Fabric Yardage Calculator — how much fabric for sewing projects
- Seam Allowance Calculator — cut dimensions with quilting seam allowances