Free quilting tool

Quilt Binding Calculator

Pick your quilt size and this quilt binding calculator works out the three numbers you actually need before you cut: how much binding to make, how many strips to cut, and how much fabric to buy. It updates as you type — no button to press.

How the maths works

Nothing fancy — this is the same pencil-and-paper method quilters have used for years, just without the arithmetic mistakes:

Perimeter = 2 × (width + length). Then add 10 inches for joining the ends and turning the corners — that gives the binding length you need to make.

Each strip is cut across the fabric, and you lose about 2 inches to selvages and trimming, so a strip gives you fabric width − 2 in of usable binding (41 in from standard 43 in quilting cotton). Strips = binding length ÷ usable length, always rounded up — half a strip is no use to anyone. Multiply the strips by your strip cut width and that is the length of fabric to buy, rounded up to the nearest 1/8 yard because that is how fabric is cut at the counter.

Bias binding is worked out with the continuous-bias square method: square side = √(binding length × strip width). That figure is an estimate — bias strips stretch and are cut from a square rather than straight across the bolt, so bias almost always uses more fabric than the straight-grain number. If your quilt has curved or scalloped edges, bias is the one you want anyway, because it bends around curves instead of fighting them.

Binding needs for common quilt sizes

Straight grain, 2.5 in strips, 43 in fabric — the defaults above:

Quilt size	Binding length	Strips to cut	Fabric to buy
Crib 36 × 52 in	186 in	5	3/8 yd
Baby 36 × 36 in	154 in	4	3/8 yd
Lap / Throw 50 × 60 in	230 in	6	1/2 yd
Twin 70 × 90 in	330 in	9	5/8 yd
Double / Full 80 × 90 in	350 in	9	5/8 yd
Queen 90 × 108 in	406 in	10	3/4 yd
King 110 × 108 in	446 in	11	7/8 yd

Quilt binding questions

Does this calculator include extra for joining the ends?

Yes. The 10 inches added to the perimeter covers joining the strip ends together and turning the four corners. It is the allowance most quilters use, and it is already in every number on this page — you do not need to add anything on top.

Should I cut my binding strips 2.25 or 2.5 inches?

2.5 in is the most common choice and gives a comfortable finished binding on a typical quilt sandwich. 2.25 in sits a little tighter and is popular for thinner quilts and for a neater look on smaller projects. If your batting is lofty, stay with 2.5 in — a too-narrow binding on a thick quilt is a fight you will lose at the corners.

Why does bias binding need more fabric?

Bias strips are cut at a 45-degree angle, usually from a square of fabric using the continuous-bias method, and the diagonal cutting wastes more at the edges than straight cuts across the bolt. The square method here — square side = √(binding length × strip width) — gives a fair estimate, but treat it as a minimum and round up when you buy.

My fabric is wider than 43 inches. Does that change anything?

Yes — wider fabric means each strip gives you more usable binding, so you may need one strip fewer. Change the fabric width field (it accepts 40–60 in, so wide backing fabrics are covered) and the strip count and yardage update on their own.

Should I buy more than the calculator says?

The number here is the honest minimum from the standard formulas. Many quilters add a little extra for shrinkage, a miscut strip, or matching a print at the joins — if you tend to fussy-cut or your fabric shrinks in the wash, rounding up one more 1/8 yard at the counter is cheap insurance. But the binding itself will not need more than the figure shown.

Binding tools worth having

Quilt Binding Calculator by SewingMachine.blog. Figures use the standard quilting formulas shown above; the bias figure is an estimate from the continuous-bias square method.