GSM explained: how to read knit-fabric weight

GSM (grams per square metre) is the single most useful number when you source a knit — it tells you how heavy, opaque, warm and structured a fabric will feel, and it drives cost and drape. Two fabrics with the same composition behave completely differently at 160 vs 320 GSM.

As a rough guide for knits: 120–170 GSM — light tees, summer base layers, linings; 180–240 GSM — everyday T-shirts, polos, dresses (the workhorse range); 280–360 GSM — heavyweight tees, hoodies, sweatshirts. Always confirm GSM against a physical swatch: finishing and relaxation shrinkage shift the number. Tell us your target weight →