Interfacing Calculator — Fusible & Sew-In Interfacing

Common interfaced pieces include collars, collar stands, cuffs, front button bands/plackets, facings (neckline, armhole), waistbands, pocket flaps, and any area that needs extra body or structure.

Fusible (iron-on) interfacing is quickest to apply and suitable for most projects. Sew-in interfacing is better for heat-sensitive fabrics, sheers, and very textured fabrics where fusible may not bond properly. Choose a weight lighter than or equal to your fabric weight.

Fusible interfacing is commonly 90cm wide. Some brands offer wider rolls at 112cm or 150cm. Woven interfacings tend to be 90cm, while non-woven fusible may be wider. Check before purchasing.

It depends on the product — always follow the manufacturer’s care notes first, as many modern fusibles (e.g. Vlieseline/Vilene non-wovens) are labelled "no pre-shrink required". If yours does shrink, soak it loosely folded in a basin of warm water for about 10 minutes, then gently squeeze out the excess and hang to dry. Do not machine wash or tumble dry fusible interfacing on its own, as that can loosen the adhesive. Pre-shrinking helps prevent bubbling or puckering when the finished garment is washed; sew-in interfacing can be pre-shrunk the same way. If you do pre-shrink, add a small shrinkage allowance under Advanced Options so you buy enough.