Fabrics and materials
What does GSM mean and which weight do I need?
Short answer
GSM means grams per square metre: the weight of one square metre of fabric. It helps compare fabrics of the same kind, but it is not a warmth rating. The right weight depends on the fabric and the product, and we confirm the exact GSM with your quote.
GSM (grams per square metre) is the weight of one square metre of fabric. One ounce per square yard is about 34 GSM. A higher GSM usually means a thicker fabric of the same kind, but GSM is not a warmth rating: warmth also depends on the fibre and how the fabric is made.
Weight classes
| Weight class | GSM |
|---|---|
| Lightweight | below about 160 GSM |
| Midweight | about 160 to 260 GSM |
| Heavyweight | above about 260 GSM |
There is no fixed rule such as "180 GSM for summer, 300 GSM for winter". The right weight depends on the fabric type, the product and how it will be used.
What matters for each product
- Balaclavas: the fabric type and GSM, the stretch, and any mesh or fleece panels.
- Beanies: the yarn, the stitch, the gauge and whether it is single or double layer. GSM is rarely quoted for knits.
- Scarves: the fibre, and whether it is knitted or woven.
- Socks: the yarn blend, the needle count and the cushioned zones.
- Ski wear: the weight is chosen for each layer.
- Caps and hats: the fabric type and the structure.
Examples from our projects
- Polyester/spandex stretch jersey (88/12) at 220 to 260 GSM for balaclavas and neck gaiters.
- A sublimated face mask at 180 GSM.
- A merino balaclava at 260 GSM.
- Knitted balaclavas at 320 and 360 GSM.
Why the fabric sheets show no GSM
Weights vary by mill and by order, so we confirm the exact GSM with your quote. Tell us how the product will be used and we suggest a suitable weight. Our Fabric Weight & GSM Guide explains the topic in more detail.
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