What Is GSM / Fabric Weight?

GSM expresses a fabric's weight per unit area. Because the value is given per square metre, it allows fabrics produced in different widths to be compared on the same scale. It is used in the same way for both woven and knitted fabrics.

In Turkish technical documents, "gramaj" (fabric weight), "weight per square metre" and "GSM" are mostly used interchangeably. In some markets, particularly for products such as denim, weight is also expressed in ounces per square yard (oz/yd²). Quotes given in different units should be converted to the same unit before they are compared.

The g/m² value tells you how many grams one square metre of fabric weighs. To measure it, a sample of a defined area is usually cut from the fabric and weighed on a precision balance, and the result is then scaled up to one square metre.

A simple calculation example

The figures below are only meant to illustrate the logic of the calculation; they do not represent any particular class of fabric.

• Sample size: 10 cm × 10 cm = 0.01 m²
• Weighing result: 2.2 g
• Fabric weight: 2.2 g ÷ 0.01 m² = 220 g/m²

The measured result can vary depending on the fabric's moisture content, the part of the fabric the sample was taken from, and whether the fabric is greige or has already been through finishing processes. So whenever you see a weight value, you should also ask at what stage and by which method it was measured. Agreeing with the supplier at the outset on which test method will be used as the reference prevents disputes later on.

Weight per square metre vs. weight per running metre: why does width matter?

Some suppliers state weight per running metre (a one-metre length across the full width). This value is written as g/m (g/mt in Turkish trade usage) and is directly linked to the width.

• g/m = g/m² × width (in metres)
• Example: for a 150 cm wide fabric of 220 g/m², 220 × 1.5 = 330 g/m
• Conversely: 330 g/m ÷ 1.5 m = 220 g/m²

Which width is used matters here. The full width including selvedges may differ from the usable width, so which of the two the calculation is based on should be stated in writing.

No. Fabric weight describes how heavy a fabric is, whereas thickness is the distance between its two faces. Two fabrics of the same weight can feel different in thickness and fullness. The main reasons for this are:

• Yarn structure: A fabric made from bulky, lofty yarns can look thicker and fuller than a fabric of the same weight made from tightly twisted yarns.
• Thread density and weave: A densely woven construction can be thin yet heavy, while a looser construction can feel bulkier at the same weight.
• Finishing: Processes such as brushing or raising can lift the surface, while processes such as pressing and calendering can flatten it and give the fabric a thinner feel.

In practice, how warm a fabric feels depends not only on its weight but also on the bulk of its structure and the air trapped within it. Fabric weight should therefore not be read as a direct equivalent of thickness or warmth.

As a general trend, lighter fabrics are preferred for spring/summer products and fuller fabrics for autumn/winter products. However, there is no summer/winter weight threshold that applies to everyone. A fabric of a given weight can be positioned as a year-round product in one collection and as a seasonal product in another.

Other factors also determine seasonal suitability: composition, the openness of the weave, air permeability, the use of lining, the garment's cut and the climate of the target market. We look in detail at how to assess these factors together in our guide to choosing summer and winter fabrics.

No. Fabric weight is a specification value, not a measure of quality. Quality is about how well a product fulfils its intended function, and it depends on many elements such as yarn quality, fibre fineness, weaving evenness, finishing, and colour and dimensional stability.

A structured jacket may call for a full-bodied fabric, whereas in a dress or shirt expected to drape fluidly, the same weight could make the garment heavy. In addition, some finishing processes can increase a fabric's weight; this alone does not make it a better fabric. You can find out how weight is assessed together with hand and drape in suiting products in our suiting fabric guide.

The right question is not "which weight is better?" but "which weight is right for this product, this end use and this target price?"

A weight value given on its own is not enough to compare two quotes. Requesting the following information together makes it easier both to compare quotes and to control bulk production:

• Weight value and unit (g/m² or g/m?)
• Tolerance range agreed in writing by both parties
• Fabric width, and whether this is the full width or the usable width
• Composition with fibre percentages
• Weave or knit structure
• Stage at which the measurement was taken (greige or finished) and the method used
• Finishing processes applied
• Code or reference of the approved sample
• End use and target season of the product

When comparing quotes, the price per metre on its own can be misleading. Even if two fabrics of different widths and weights appear to have the same price per metre, their cost per unit area and their cutting yield are different. You can read why composition is also a deciding factor alongside weight in our fabric composition guide.

For an overview of the different fabric groups, you can visit our fabrics page. When sending an enquiry to Arkadaş Tekstil, sharing your target weight, width and composition together speeds up the evaluation; you can use the Request a Quote page for this.