Quilt Binding
Quilt binding length from the quilt size plus your overlap, the strips to cut at your strip width and join allowance, and the yardage — straight or bias.
How long the binding must be, how many strips of your width the fabric yields once each diagonal join is allowed for, the fabric to buy, and the square a bias binding needs instead.
Example: A 60 × 72 in quilt with 12 in overlap needs 276 in of binding; 2.5 in strips from 42 in fabric losing 2.5 in per join give 39.5 in each, so 7 strips — 17.5 in = 0.49 yd.
Perimeter plus
overlap.
How the binding length is found, why each join costs a strip width, how strips become yardage, and how bias binding is estimated instead.
Length
The binding runs round the quilt: twice the width plus twice the length, plus the overlap you allow for turning the four corners and joining the ends — a figure that depends on your join method and is yours to enter.
Strips and joins
Straight-grain binding is cut in strips across the usable fabric width (selvedge to selvedge, less the selvedges). Strips are joined on the diagonal so the seam bulk is spread, and each join uses up about one strip width of length; that allowance is subtracted from every strip. The number of strips is the binding length divided by the usable length per strip, rounded up, and the fabric is strips × strip width.
Bias binding
Bias binding is cut at 45° and estimated by area: a square of side √(length × strip width), or a full-width rectangle of the same area when the square is wider than the fabric. It is the same figure Bias Binding gives, without a margin.
What the number does not settle
Strip width for a given finished binding width depends on the seam and the thickness of the quilt sandwich; common choices are yours to enter, not embedded. Scrappy or pieced bindings, flanges and facings are not modelled. Inputs stay in your browser; the same anonymous usage counts as the rest of the site apply.