How to Calculate Quilt Binding Strips and Yardage
Calculate quilt binding length by doubling the quilt width plus length, then adding an overlap buffer, usually twelve inches in this tool. Divide by usable fabric width and round up for the basic strip count. Multiply strips by strip width and divide by thirty-six to obtain fabric yards before purchase rounding.
The optional diagonal-join adjustment accounts for length lost when strips are joined at an angle. Each join consumes approximately one strip width from the combined usable length. The calculator finds enough strips to cover the perimeter and buffer after that loss. For a 60 by 80-inch quilt, the perimeter is 280 inches; adding 12 gives 292 inches. Eight 40-inch strips at 2.5 inches wide require 20 inches of fabric, or about 0.56 yard. The purchase estimate rounds upward to 0.625 yard.
Width of fabric, often abbreviated WOF, means the usable strip length after excluding selvages. The default binding WOF is 40 inches. Do not substitute the bolt label without checking the actual usable width. Strip-width pills cover 2, 2.25, 2.5, and 3 inches, allowing you to compare narrower or wider binding. The calculations describe straight-grain WOF strips, not the diagonal cutting layout needed to produce bias binding.
Example Quilt Sizes and Binding Yardage Table
| Example size | Dimensions (in) | Basic / diagonal strips | Buy yards, 2.5-inch strips |
|---|---|---|---|
| Baby | 36 × 48 | 5 / 5 | 0.375 |
| Lap | 50 × 60 | 6 / 7 | 0.500 |
| Twin | 70 × 90 | 9 / 9 | 0.625 |
| Full | 80 × 90 | 9 / 10 | 0.750 |
| Queen | 90 × 100 | 10 / 11 | 0.875 |
| King | 108 × 108 | 12 / 12 | 0.875 |
Illustrative top sizes, not universal bedding standards. Assumes 40-inch usable WOF, 12-inch overlap, diagonal joins, and purchase rounding up to 1/8 yard.
How to Plan Binding and Backing Cuts
1. Measure the finished quilt top
Enter the top width and length in inches. Use the actual measured dimensions when available rather than relying on a bed-size label. Choose the binding strip width required by your finishing method.
2. Set usable width and overlap
Enter usable WOF and the extra length needed for corners and joining the ends. Leave diagonal-join allowance enabled when joining strips diagonally. Read both the basic strip count and the adjusted count before cutting.
3. Compare backing layouts
Enable backing and enter the overage, seam allowance, and usable widths after removing selvages. Defaults are four inches per edge, half-inch seams, and 44-inch and 108-inch comparison widths. Compare vertical and horizontal seams. The display gives the panel count and cut length for each option.
4. Round up and verify the quilt plan
Buy at least the displayed rounded amount, allowing separately for shrinkage and matching prints. Confirm overage, seam position, and pressing requirements with the quilter before cutting backing. Keep binding and backing purchases separate.
Quilt Backing Fabric: Standard 44-Inch vs 108-Inch Extra-Wide
A 60 by 80-inch top needs a 68 by 88-inch backing under the four-inch-overage rule. Two 44-inch panels joined vertically require two 88-inch lengths, or approximately 4.89 yards before rounding. Three horizontal panels require three 68-inch lengths, or approximately 5.67 yards. A 108-inch backing can fit the 88-inch side across the bolt and needs a 68-inch cut length, approximately 1.89 yards. These comparisons account for half-inch joining seams, but not print matching or additional shrinkage. The wider option is not always seamless: very large quilts can exceed 108 inches even after rotation.
Frequently Asked Questions
Should I cut binding on the straight grain or bias?
Straight-grain strips are commonly used for straight quilt edges and are what this tool calculates. Bias binding stretches around curves and scallops more readily, but needs a different cutting layout and yardage calculation. Choose the method appropriate to the quilt edge and your pattern.
How wide should my binding strips be?
The right strip width depends on the desired finished binding, batting thickness, seam allowance, and finishing method. The tool offers 2, 2.25, 2.5, and 3 inches, with 2.5 inches selected initially. Test a short section instead of assuming one width suits every quilt.
How much extra backing is needed for longarm quilting?
The default is four inches on each side, adding eight inches to both top dimensions. Change the overage field to match your quilter’s requirements. Longarm quilters can require a different amount for loading and clamping. Follow your quilter’s instructions if they exceed this default.
Why does diagonal joining sometimes add a strip?
A diagonal seam reduces the combined usable length by approximately the binding strip width. Several joins can use enough length to make the basic perimeter-divided-by-WOF count insufficient. The adjusted count covers that loss as well as the entered overlap buffer.
Are 44-inch and 108-inch backing widths always usable?
No. These are comparison widths treated as usable by the backing model. A real bolt may include selvages or shrink after washing. Enter your measured usable widths in the backing fields; narrower fabric can change how many panels are needed. Seam allowance is also adjustable and is deducted twice at each join.
Does the binding yardage include the backing?
No. Binding and backing are separate results and usually separate fabric purchases. The binding estimate covers WOF strips; the backing estimates cover rectangles plus the entered edge overage and joining seams. Neither result includes batting.