Fabric GSM Explained: Choosing Fabric Weight for T-Shirts, Hoodies and Sportswear

GSM (grams per square metre) measures how heavy a fabric is: the higher the number, the heavier and usually thicker the fabric. As a rough guide, everyday T-shirts sit around 140–200 GSM, polo shirts around 180–240 GSM, and fleece hoodies and sweatshirts around 260–400 GSM. The right weight depends on the garment's look, season and price, not on a single "best" number.

Typical weight ranges by garment

• T-shirts: about 120–150 GSM for light, drapey tees; 160–200 GSM for everyday tees; 200–260 GSM for heavyweight, structured tees
• Polo shirts (piqué): about 180–240 GSM
• Sweatshirts and hoodies (fleece or French terry): about 260–400 GSM, with 300–350 GSM a common mid-weight
• Performance and training tops (polyester knits): about 120–180 GSM, chosen for breathability and stretch
• Leggings and compression wear: often 200–300 GSM, where stretch and opacity matter as much as weight

These ranges are typical starting points across the industry. Mills describe fabrics differently, so always confirm weight on the actual fabric or a swatch.

GSM is not the whole story

• Fibre: cotton, polyester and blends of the same weight feel and perform differently
• Knit or weave: single jersey, piqué, rib, interlock and fleece of similar weight drape and stretch differently
• Yarn: combed and ring-spun cottons feel smoother than open-end yarns at the same weight
• Finishing: brushing, washing and enzyme treatments change handfeel and can change measured weight
• Shrinkage: ask how the fabric has been pre-treated and what shrinkage to expect after washing

How to choose a weight

1. Start from a reference garment you like and ask for its fabric weight to be checked
2. Match weight to season and use: lighter for summer and sport, heavier for structure and warmth
3. Consider print and embroidery: very light fabrics can pucker under heavy decoration
4. Approve the fabric on the sample, not only on a specification sheet

Put the weight in your specification

Write the agreed weight, composition and fabric type into your specification (for example, "180 GSM, 100% combed cotton single jersey") with a tolerance agreed with your manufacturer. The approved sample then becomes the reference for bulk production.