What Is Fabric GSM?

GSM (also known as GM/2) is an abbreviation of “Grams per Square Metre” and is the metric in which fabric is weighed. GSM is related to thickness, and generally speaking the heavier the weight, the thicker the fabric will be. With that being said however, due to varying weights of different fibres, the GSM cannot accurately determine the thickness in mm of a fabric.

No item has a “standard” GSM, however because GSM is a unit of weight, it can determine the application of a fabric.

Because heavier weight fabrics use more raw fibre and have a longer weaving time, they do cost more than lower weight equivalents. It’s also worth noting that GSM can also be measured in Imperial units – ounces (oz) in particular. You can easily convert between gsm and oz however; for example, a 6oz fabric is equivalent to 203gsm.

Traditionally some fabrics, denim for example, are weighed in ounces, but GSM is the modern standard for fabric weight measurement.

As a real world scenario, t-shirts are commonly made from fabrics weighing between 160 and 220gsm, with a 160gsm fabric being the thinner and more lightweight version than the 220gsm option. Some fashion trends require a heavier weight, whilst practical applications like gym and fitness wear would see a lighter weight fabric being more desirable.