Definition
Muslin fabric, in American usage, is an inexpensive unbleached plain-weave cotton used for test garments; in British English this fabric is called calico.
The same word means different things depending on where you sew:
| Where | Muslin means | The test fabric is called |
|---|---|---|
| United States | Plain, unbleached cotton for test garments, and the test garment itself | Muslin |
| United Kingdom, Australia | A fine, loosely woven, sheer cotton, as in baby muslin cloths | Calico |
| France and fashion schools | Toile is both the cloth and the test garment | Toile |
In American sewing, muslin comes in light, medium and heavy weights, unbleached or bleached, usually 110 to 150 cm (45 to 60 in) wide. It is inexpensive, takes pen and chalk marks well, and shows wrinkles and pulling clearly, which is why it is the default for testing fit.
Choose the weight closest to your final fabric: light muslin for blouses and dresses, heavier for trousers and jackets. For a knit garment, or a fluid fabric like viscose, a muslin test will mislead you; use an inexpensive fabric with the same stretch or drape instead.
Muslin is also useful as underlining, as a pressing cloth and as a bag lining. Prewash it if you plan to wear the test garment, since it shrinks. The process of making a test garment is described under toile and in making a toile.