Fabric & decoration
Knit fabrics and GSM, explained for apparel buyers
GSM (grams per square metre) is the weight of a fabric. For knitwear, pick the fabric structure first: jersey for T-shirts, piqué for polos, terry or fleece for sweatshirts, interlock or ponte for sets. Then pick the GSM that suits the climate, the use and the feel you want.
Key takeaways
- T-shirts use 100% cotton single jersey, typically 180–260 GSM.
- Polo shirts use piqué (4-way or 6-way), typically 200–260 GSM, with flat-knit collars.
- Hoodies and sweatshirts use French terry or brushed fleece, typically 320–400 GSM (up to 480).
- Casual sets use interlock, ponte or terry, at around 0.8–1.2 kg of fabric per two-piece set.
- Spandex rib runs 220–300 GSM for T-shirt collars and 380–550 GSM for sweatshirt cuffs and hems.
What GSM tells you, and what it doesn’t
GSM is the weight of one square metre of fabric in grams. It is the quickest way to compare two fabrics of the same type: a 240 GSM jersey will feel more substantial, less see-through and more structured than a 180 GSM jersey.
GSM says nothing about fibre quality, yarn count, how tightly the fabric is knitted, or how it was dyed and finished. Two 200 GSM fabrics can feel very different, so compare physical swatches before bulk.
GSM also drives cost and logistics. Fabric is bought by the kilogram, so a heavier fabric means more fabric per garment, a higher price, heavier cartons and fewer pieces per container.
The five knit fabrics behind most uniforms
| Fabric | Structure | Typical GSM | Used for |
|---|---|---|---|
| Single jersey | Plain knit, smooth face | 180–260 | T-shirts |
| Piqué | Textured honeycomb knit (4-way or 6-way) | 200–260 | Polo shirts |
| French terry | Smooth face, looped back | 320–480 | Sweatshirts, hoodies, sets |
| Brushed fleece | Smooth face, brushed back | 320–480 | Winter hoodies, sweatshirts |
| Interlock / ponte | Double knit, stable | — | Casual and athleisure sets (fabric use is quoted per set, ≈ 0.8–1.2 kg, not in GSM) |
Single jersey
The classic T-shirt fabric is smooth on the face, with visible loops on the back. It stretches, drapes and prints well. At 180 GSM it is light and breathable, and at 240–260 GSM it becomes a heavyweight tee with more body.
Piqué
A textured knit with a small raised pattern. The texture lets air circulate and hides creasing, which is why it is the standard for polo shirts in uniforms. Piqué polos are paired with flat-knit collars and cuffs, knitted separately on flat machines.
French terry and fleece
Both have a looped back. French terry keeps the loops and breathes well, which suits spring, autumn and active use. Fleece has the loops brushed into a soft nap and is warmer. For school sweatshirts and workwear hoodies, 320–400 GSM is a common working range. Above that you are into heavyweight territory.
Interlock and ponte
These are double-knit fabrics, stable, smooth on both sides and resistant to curling. They hold their shape, so they work well for tracksuits, PE kits and two-piece sets.
Rib, the fabric you notice only when it fails
Collars, cuffs and hems are made from rib, a stretchy knit, usually with a little spandex, that recovers its shape. For T-shirt collars our standard spec is 1×1 or 2×2 rib, 95% cotton / 5% spandex, 220–300 GSM, dyed in the same lot as the body so collar and body match. Sweatshirt cuffs and hems use 2×2 high-stretch spandex rib, 380–550 GSM.
How to choose
- Start with the garment, which fixes the fabric family (jersey, piqué, terry/fleece, interlock).
- Set the climate and season: lighter for hot climates and summer, heavier for winter.
- Consider the use. Promotional and event wear can go lighter, daily uniforms usually sit mid-range for durability, and premium retail tends heavier.
- Check the decoration, since heavy embroidery and appliqué need a fabric with enough body to support them.
- Request swatches of two neighbouring weights and compare them in hand.
Final thoughts
Choose the fabric family by garment, then use GSM to tune for climate, use and decoration. Treat the numbers as a starting point and confirm the choice with swatches in hand. If you are specifying for a uniform program, tell us how often the garments are washed and worn. That matters more than any single number.