Quilt Bias Binding Calculator: Bias Strips and Yardage for Curved Edges

Work out bias binding before you cut. Enter finished quilt size or measured edge length, strip width and fabric width, and see binding length, strips and yardage, with the formula in steps.

Calculate your bias binding

How do you want to measure the edge?

For a rectangle, enter width and length below. For a curved, scalloped or round quilt, choose total edge length, and measure around the edge with a flexible tape, without stretching the quilt.

Finished quilt width in

Finished quilt length in

Binding strip width, cut in

Binding strip width is the cut width of each bias strip, not the finished width on the quilt edge. A common cut width for double fold binding is 2.5 inches.

Extra for joins, corners and overlap in

Extra length covers joining strips, easing around curves, and the final overlap where binding ends meet. The default is 15 inches for bias binding, a little more than straight binding, because bias stretches and needs gentler handling. Change it if your method needs more or less.

Fabric width

Seam allowance for joined strips in

Seam allowance is used only when strips are joined end to end. It is the amount lost at each join.

This calculator works out bias binding for curved edges, and for rectangle quilts where you want bias binding. For straight edges with straight grain binding, use the Binding Calculator. Binding is calculated from finished quilt size or total edge length, after borders are added, not from the original top size.

Your result

Enter your measurements, then calculate.

How the calculator works

Step 1: Edge length

For a rectangle quilt, edge length equals 2 times finished width plus 2 times finished length. For a curved, scalloped or round quilt, edge length is the total length you measure around the edge, with a flexible tape, without stretching the quilt. Use finished size or measured edge length, after borders are added, because binding goes around the finished edge, not the original top.

Step 2: Bias length needed

Bias length needed equals edge length plus extra for joins, curves and overlap. The default extra is 15 inches for bias binding. Change it if your method needs more or less.

Step 3: Strips needed

If bias length needed fits in one fabric width, you need 1 strip. If not, each extra strip adds fabric width minus seam allowance, because seam allowance is lost at each join. Strips are rounded up.

Step 4: Yardage

Fabric length to buy equals strips times binding strip width, because each strip is binding strip width wide. Exact yardage equals fabric length divided by 36 in inch mode. Yardage to buy is exact yardage rounded up to the nearest 1/8 yard. In centimetre mode, metres to buy are rounded up to the nearest 0.1 metre. The unit toggle changes all inputs, outputs and rounding together.

Assumptions, shown next to the result

Fabric width is the nominal width. Seam allowance applies only at strip joins. No extra is added for cutting mistakes or shrinkage, beyond the extra length you enter for joins, curves and overlap. Bias strips stretch, so measure edge length without stretching, and handle bias strips gently while cutting and sewing.

Bias binding and straight grain binding are different

Bias binding is cut on the diagonal, so it stretches around curves. Straight grain binding is cut along the grain, and it suits straight edges. Do not use straight grain binding yardage for a curved edge without checking edge length, because curves need a measured edge length, not a rectangle perimeter. Use the Binding Calculator for straight edges.

Yardage chart by quilt size

This chart uses the same formula as the calculator: binding strip width 2.5 inches, 44 inch fabric, 0.5 inch seam allowance, extra 15 inches, yardage rounded up to the nearest 1/8 yard. Finished sizes are after a 4 inch border, as in the border chart. Yardage matches the straight binding chart for these sizes, because strip count is the same. The difference with bias binding is in cutting and handling, not in yardage steps for these sizes.

Quilt size	Finished size	Edge length	Strips	Yardage to buy
Baby	44 by 56 in	200 in	5	0.38 yards
Lap	58 by 68 in	252 in	7	0.50 yards
Twin	76 by 96 in	344 in	9	0.63 yards
Full	88 by 100 in	376 in	9	0.63 yards
Queen	98 by 116 in	428 in	11	0.88 yards
King	116 by 116 in	464 in	11	0.88 yards

Chart yardage is a guide for the sizes shown, for rectangle quilts. For a curved or round quilt, measure total edge length directly, and use the calculator above with that length. Your exact edge length, binding strip width and fabric width may give a different result.

Worked example, checked against the calculator

Curved edge quilt, total edge length measured at 320 inches, binding strip width 2.5 inches, fabric width 44 inches, seam allowance 0.5 inch, extra 15 inches.

Edge length: 320 inches, measured around the edge, without stretching the quilt.

Bias length needed: 320 plus 15 equals 335 inches.

Strips needed: 335 inches does not fit in 44 inches. Each extra strip adds 43.5 inches. Strips equal 1 plus the ceiling of (335 minus 44) divided by 43.5, which is 8 strips.

Fabric length to buy: 8 times 2.5 equals 20 inches. Exact yardage: 20 divided by 36 equals 0.56 yards. Yardage to buy, rounded up to the nearest 1/8 yard, equals 0.63 yards.

Frequently asked questions

How do I calculate bias binding?

Measure total edge length around the quilt, including curves, add extra for joining strips, corners and final overlap, work out strips needed from fabric width, and convert strips times binding strip width to yardage.

How much fabric do I need for bias binding?

It depends on total edge length, binding strip width and fabric width. Use the calculator above with your edge length or finished quilt size, binding strip width and fabric width. The result shows edge length, bias length needed, strips needed and yardage to buy.

When should I use bias binding instead of straight grain binding?

Use bias binding for curved edges, scallops and round quilts, because bias strips stretch around curves. Use straight grain binding for straight edges. Straight grain binding will not stretch around a curve without puckering.

Do bias strips need seam allowance?

Yes, when strips are joined end to end. Each join loses seam allowance from usable strip length. This calculator accounts for seam allowance when it works out how many strips you need.

Why is extra length higher for bias binding?

Because bias fabric stretches and needs gentler handling around curves, and because joining bias strips and finishing the final overlap needs a little more room. The calculator default is 15 inches, compared with 12 inches for straight binding. Change it if your method needs more or less.

How do I measure a curved edge for binding?

Use a flexible tape, follow the edge closely, and do not stretch the quilt or the tape. Measure twice, and use the larger number if measurements differ, so binding does not come up short on a curve.

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