The abbreviation for fabric GSM stands for grams per square meter. It is the weight of a square meter of fabric in metric measurements. The higher the GSM number, the denser the weight of the fabric. This is an important indicator of what to use the fabric for because it shows the thickness and quality of the fabric. The GSM of denim, for example, is higher than the weight of soft chiffon. With a higher fabric GSM, denim will be more hard-wearing and lasting compared with chiffon.
What is Fabric GSM?
Fabric GSM can be defined as the grams per meter of fabric. It is a metric measurement that is used. While metric measurements are predominantly used (g/m2), occasionally a fabric may be measured in imperial weights and marked as ounces per yard squared (oz/yd2).
- 1 ounce = 28.3 grams
- 1 gram = 0.035 ounces
- 1 yard = 0.9 meters
- 1 meter = 1.09 yards
The GSM of fabrics will also affect the price because more raw materials are used in the manufacture of thicker, higher density GSM quantities.
These facts are important for the merchandiser who must know the right GSM of the fabric so it can be assigned for the right purpose. Winter suits for example need to be warm and a high GSM helps with that aspect of the garment. The GSM also determines how the fabric drapes and contributes to its durability.
Fabric GSM Qualities
There are different qualities looked for in the fabrics according to their GSM weight measurement. These are the ability to ‘breathe’, the way they fit and drape, as well as their weight.
Ability to breathe
Lightweight fabrics are able to ‘breathe’ more and are suited to summer clothes. This means they enable a cool flow of air to circulate through the lightweight fabric. Cotton and light linens make up into summer clothes that have this quality.
A good weight for a lightweight suit is 210 GSM to 230 GSM range as it is cool in summer and light enough in winter to add a cardigan underneath for some added warmth. The heavier GSM fabrics keep you warmer and are suited to heavy suits and clothing for winter.
Fit and Drape
Tailors enjoy working with heavier weighted fabrics. They drape downwards and hold their shape better than light weighted fabrics. The smart fitted look for a top-quality suit comes from the weight and drape of the fabric. Lighter weights used for suits tend to crease and drift in the wind. Lighter weight fabrics can catch on other items of clothing, while thicker fabrics hold their shape. However, a thicker weight of the fabric can increase the appearance of the size of the person wearing them.
Further Reading: Fabric Drape for Sewing
Fabric GSM Weight
There are three different categories of weight. They range from light weight to medium weight and heavy weight. Within those categories there are weights designed for specific purposes like shirting, towelling and wool suiting. Lightweight fabrics weigh between 180 GSM and 230 GSM.
Linens, cotton, fine wools and silks fit into this lightweight category. Medium weight is between 240 GSM to 290 GSM and this includes wool, thicker cotton as well as some silk blends. Thick wool and tweeds fall into the heavyweight group and weigh higher than 300 GSM.
Different weights and classes of fabric include the following:
Wool comes in a wide range of weights. Weight and thread count affects wool quality and suitability for different items of clothing.
Shirting or Shirt Fabrics:
A good quality dress shirt will usually be made of cotton, linen or a blend of the two. The thickness will vary between the 100 – 200 GSM range. This will determine the top class quality of the shirt.
Toweling and Bath Towels:
A really thick, fluffy bath towel should have a high GSM. Look for at least 400 GSM to have a really thick, absorbent towel. It is advisable to choose a towel with the GSM in mind because in that way you will find the best quality. Manufacturers can fluff up towels to appear absorbent, but it is the GSM count that really tells the quality of the towel.
Sheets and Bed Linen
For bedsheets, most people want a fabric GSM of 90 to 120 in order for them to be comfortable, breathable and still feel soft. A higher GSM in sheets will make them feel heavier and more luxurious. They will also be more durable.
How to Calculate Fabric GSM
The most commonly used method to calculate the GSM is by using a GSM cutter machine. Five different samples of the fabric are cut using the machine. The mean value of these samples is multiplied by 100 and the result is the GSM.
A count of 300 GSM means a meter of the fabric weighs 300gm. In the standard measures, 30 to 150 GSM is lightweight. A measure of 150 to 350 GSM is medium weight and more than 350 GSM is heavyweight.
The standard weight for T-shirts is 180 GSM, but some T-shirts may fall into the 130 -150 GSM range.
Thread Count vs Fabric GSM: Thread count is not the same as the fabric GSM. GSM is purely weight-related while thread count measures the number of threads per square inch to create the fabric. When buying sheets, be aware that thread counts can be manipulated.
Categories of Fabric GSM
Lightweight fabrics, the lowest GSM category, include chiffon, linen, organza, cheesecloth, lace, voile and mesh.
Medium-weight fabrics, the middle range of fabric GSM measurements, include face towels, hand towels, velvet, sateen, chartreuse and taffeta.
Heavyweight fabrics, the highest range of the GSM range, are found as bath and good quality pool towels needing a high absorbency. Heavyweight fabrics are used for upholstery fabrics, canvas, pure denim and poplin.
Fabric GSM Chart
|Light||8-200||Voile, Chiffon, Lace, Mesh, Light Cotton|
|Medium||201-300||Toweling, Velvet, Tafeta|
|Heavy||300-400||Canvas. Wool, Denim|
|Extra Heavy||400-500||Thick Denim, Coated Fabrics|
Fabric GSM - In Conclusion
There is value in knowing the GSM or the weight of the fabric. It tells you the overall quality and durability of the fabric and is especially useful for manufacturers. An upmarket linen shirt with a high GSM will be a better quality and a more expensive item because the fabric had a higher GSM count. The fabric GSM is really an indicator of quality and quantity linked to the content of the fabric.
The weight and durability are considered by manufacturers through the GSM measure. In the final production of an item of clothing, or piece of fabric, the GSM is the measure of the gram weight of the end product. It is a metric measure and a key indicator of quality.