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Piped (Corded) Cushion Fabric Calculator
A piped cushion is a knife-edge (flat, no boxing) cushion with corded welt sewn into the seam around the edge. The welt is what most calculators forget: it needs its own strip of fabric, cut as a continuous run equal to the cushion perimeter, wide enough to wrap the cord plus two seam allowances.
Cutting list
| Piece | Qty | Size |
|---|
Cutting layout
Typical sizes
Throw-cushion sizes are commonly 16, 18, 20 or 22 in square (41, 46, 51, 56 cm); welt cord is usually 4/32–6/32 in (3–5 mm) diameter for cushions that size, needing a strip about 1.5–1.75 in (4–4.5 cm) wide.
Where this goes wrong
Welt strips are traditionally cut on the bias so they curve smoothly around corners without puckering. This calculator estimates a straight-of-grain strip (simpler, less waste) — add roughly 10% to the welt figure if you plan to cut on the bias. Match the welt fabric grain to the cushion front on solid or subtly patterned fabrics; on bold prints a contrast welt often looks more deliberate than a near-miss match.
Seam allowance
Seam allowance 1/2 in (1.3 cm) is standard; the welt strip width already includes its own allowance in the figure below.