T-Shirt GSM Guide: Lightweight vs Heavyweight Explained (Chart)

By The Clothing Game, founded in the UK · Last updated: 28 October 2026

GSM (grams per square metre) is the weight of a fabric, and the most-used number for describing how thick a t-shirt feels. As a rough guide, lightweight tees are around 130–190 GSM, midweight 200–290 GSM, and heavyweight 300+ GSM (Tapstitch). Streetwear brands usually sell "heavyweight" tees in the 240–300+ GSM range for a structured, boxy drape.

What does GSM mean on a t-shirt?

GSM is the mass in grams of one square metre of fabric. A higher GSM means more cotton per square metre, so the fabric is usually thicker, more opaque and holds its shape better. GSM measures weight, not quality: a well-knitted 220 GSM combed cotton can outperform a poorly made 280 GSM.

T-shirt GSM chart

Weight class	GSM range	Feel	Best for
Lightweight	130–190	Soft, drapey, slightly see-through in light colours	Summer tees, promo merch, layering
Midweight	200–290	Substantial, everyday premium	Most fashion and brand tees
Heavyweight	300+	Thick, structured, boxy	Streetwear, oversized and boxy fits

Ranges vary between suppliers; these follow Tapstitch's GSM guide.

What GSM should a streetwear t-shirt be?

For a boxy or oversized streetwear tee, most brands land between 240 and 300 GSM. The weight lets the shoulders and body hold a square shape instead of collapsing. Pair it with a thicker neck rib (2.5–3.5 cm), or a heavy tee can look like a basic with a thin collar.

GSM for hoodies and sweatshirts

Fleece is heavier than jersey. Mid-range hoodies tend to sit around 300–350 GSM, and premium streetwear hoodies often go 400–500 GSM. Always confirm whether a quoted GSM is before or after washing, because garment dyeing and washing change the final weight and size.

Does GSM affect shrinkage and cost?

• Cost: more GSM = more cotton = higher fabric cost per unit.
• Shrinkage: driven by fibre, knit and finishing more than GSM. Ask for pre-shrunk or garment-washed fabric, and add a shrinkage tolerance to your tech pack.
• Printing: heavier, tighter knits give a cleaner base for screen printing and puff print.

How to put GSM in a tech pack

Write the full fabric spec, not just a number:

Body: 100% combed cotton jersey, 280 GSM (finished, after wash), garment-dyed. Rib: 1x1 cotton rib, 3 cm width.

Our Tech Pack Template has dedicated fields for fabric, GSM, washes and rib, so the factory gets it in a format they recognise. Need a fit to match the weight? The T-Shirt Mock-Up Pack includes boxy, cropped boxy, oversized and relaxed bodies with 1.5, 2.5 and 3.5 cm crew ribs. Not sure what else goes in a spec? Read what is a tech pack.

FAQ

Is 180 GSM good for a t-shirt?

180 GSM is a standard lightweight tee: comfortable and cheap, but it won't hold a boxy shape.

Is 300 GSM too heavy for a t-shirt?

Not for streetwear. 300 GSM is the start of "heavyweight" and gives a structured, premium feel, though it's warm in summer.

Higher GSM = better quality?

No. GSM is weight. Quality also depends on cotton type (combed, ring-spun), knit density and finishing.

Source: Tapstitch, "T-Shirt GSM Explained".