Grams per square metre explained in practice

Short answer: The number tells you how heavy the fabric is. Under one hundred and forty is thin, around one hundred and eighty is an ordinary t-shirt, and above two hundred and fifty is sweat fabric.

What the number measures

Grams per square metre is the weight of the fabric relative to its area. It says something about thickness and therefore about warmth, opacity and durability. It says nothing about how soft the fabric is.

The common levels

Under one hundred and forty is used for thin tops and summer nightwear. One hundred and fifty to two hundred is standard in t-shirts and underwear. Above two hundred and fifty is used for sweatshirts and joggers. See bamboo t-shirts for men.

Heavy is not the same as good

A heavy fabric is warmer and more opaque, but not automatically better. For summer and for underwear a light fabric is better. Choose by purpose rather than by number. See bamboo underwear for women.

Transparency

Light colours in thin fabric can be see through. If a white t-shirt has to work without an undershirt, choose at least one hundred and eighty. See sweat clothing.

Frequently asked questions

Where do I find the number

Often in the product description. If it is not stated, the weight of the garment says nearly the same thing.

Is thick fabric always more durable

Often, but knit type and yarn quality matter just as much.

What is best for summer nightwear

Around one hundred and forty to one hundred and sixty, meaning light enough to cool.