Understanding Fabric Weight
Weight is an important component when it comes to choosing the right fabric for your project. While most patterns have suggestions that specify type of fabric; e.g. broadcloth, jersey, denim; they don’t always mention the fabric weight. Intuition often plays a big role in fabric choice. If you are sewing a blouse you instinctively look for a top weight fabric; for slacks a bottom weight and for a winter coat a heavy weight.
Some fabrics just naturally fall into certain categories: Chiffon is extra light but can be anywhere from 30 g to 100 g. Voile, batiste and lawn are light weight fabrics that fall somewhere between 70 g and 145 g. Dye and printing can also affect the fabric weight. Other fabrics are described by their weave and can come in several different weights; e.g. sateen, satin, crepe, broadcloth, twill, challis, poplin, microfibre, jersey. Fabrics described by content are available in different weaves and weights: e.g. silk, linen, hemp, cotton, viscose, polyester, rayon.
Denim seems to be in a category all its own, coming in various weights, content and colours, so particular attention needs to be paid when making a selection. Fabric described as denim shirting is often not denim at all but an indigo or blue dyed chambray or other shirting.
There are two systems of fabric weight categorization, imperial and metric. Both are represented in the above chart: the larger the number, the heavier the fabric. Some fabrics are named by weight; e.g. 12 oz. denim, 8 oz. terry cloth.
When shopping in a store, you can feel the weight of the fabric even though the weight is often not given on the bolt label. Online is a different story. You are relying on the accuracy of the description. If the fabric weight is given, then you will have a better idea. But suggested uses are more helpful. Drape or hand is another important factor.
Ultimately, the purchaser is the final decision maker and crossing the boundaries can be a creative endeavour. A jacket sewn in blouse weight fabric can make a stunning topper. A drapey suiting weight fabric can become an amazing shirt.
Sources for the chart include American & Efird, Schmetz, Coats & Clark, Wikipedia and my own sewing experience.