GSM stands for grams per square metre. It is the standard way to state how heavy a fabric is, and it tells you a lot about how a garment will feel, drape and wear. It is also one of the first things a buyer or sourcing manager asks for.
What GSM tells you, and what it doesn’t
- Higher GSM means a heavier, usually denser fabric: warmer, more opaque and often more durable.
- Lower GSM means a lighter fabric: cooler, more fluid and often more see-through.
- GSM is not quality. A fine 120 GSM shirting can cost more than a coarse 200 GSM one. Fibre, yarn count, weave and finish matter as much as weight.
Typical weights by garment
These are common ranges, not fixed rules. Every mill and brand has its own preferences.
| Garment or fabric | Typical GSM | Feel |
|---|---|---|
| Voile, lawn, light summer shirting | 60 – 100 | Very light, often sheer |
| Poplin and everyday shirting | 100 – 140 | Light, crisp |
| Linen shirting | 130 – 180 | Light to medium, textured |
| T-shirt jersey | 140 – 220 | Light tees to heavyweight tees |
| Chinos and twill trousers | 200 – 300 | Medium to heavy |
| Sweatshirt fleece | 250 – 400 | Heavy, warm |
| Denim (often stated in oz) | about 340 – 475 | Roughly 10 – 14 oz |
GSM and ounces
US mills and denim makers often state weight in ounces per square yard. To convert:
- oz per square yard × 33.9 = GSM. So 12 oz denim is about 407 GSM.
- GSM ÷ 33.9 = oz per square yard. So a 180 GSM tee is about 5.3 oz.
How GSM is measured
A circular cutter takes a sample of exactly 100 square centimetres, which is weighed on a precision scale and multiplied by 100. Mills test several points across the width, because weight can vary slightly from edge to centre.
Putting GSM on your product pages
Shoppers can’t touch fabric online, so weight helps them picture it. Show it next to composition and fit, with a few words that translate the number:
- “100% cotton jersey, 180 GSM: a mid-weight tee that isn’t see-through.”
- “Linen, 160 GSM: light and breathable, with a soft natural crease.”
Brands that explain fabric clearly tend to get fewer “is this see-through?” questions and fewer returns over the wrong expectations.
ATI Sutra
Show GSM and fabric details where buyers look
We build stores and catalogue websites that put composition, weight and care on every product.