Insights · 6 min read
Choosing the Right GSM for Your T-Shirt Line
GSM — grams per square metre — is the single most useful number when specifying a T-shirt, and also the most misunderstood. It does not tell you how a shirt feels; it tells you how much fabric is in it. Two shirts at 180 gsm can feel completely different depending on the yarn, the knit and the finish.
What gsm actually measures
GSM is the weight of one square metre of the fabric. It is a density measure, not a quality measure. A 140 gsm ring-spun combed cotton can be a better garment than a poorly made 220 gsm tee — the number describes how much fibre is there, not how good the fibre is.
The bands, and what they mean in the hand
140–160 gsm — light. You can see your hand through it in a light colour. Suits summer ranges, promotional work and layered use. It feels thin and most customers read it as inexpensive, which may be exactly what you want in a promotional product.
180–200 gsm — the retail standard. This is where most private label programmes sit. It is substantial enough to hold a shape, opaque in white, and it takes screen print well. If you are building a basic range and you are unsure, this is the safe answer.
210–240 gsm — premium basic. Noticeably heavier in the hand, better drape, less prone to collar distortion. This is the band where a tee starts to justify a higher retail price.
250–320 gsm — heavyweight. Streetwear territory. The garment holds a boxy silhouette on its own rather than following the body, which is the whole point of the look.
How weight interacts with price
Fabric is usually the largest single cost in a T-shirt, so gsm moves your unit cost almost linearly. Going from 160 to 240 gsm typically adds a meaningful percentage to the fabric cost, not a few cents. That is fine if your retail price supports it — the mistake is specifying heavyweight fabric and then having no margin left to decorate it properly.
The mistakes we see most often
Choosing on weight alone. Yarn quality and knit matter as much. A compacted, ring-spun 180 gsm will outperform a loosely knit 200 gsm every time.
Forgetting shrinkage. Heavier cotton generally shrinks more. If your size chart has to hold after washing, specify a pre-shrunk or compacted finish — and confirm it at sampling, not after bulk.
Specifying heavyweight then printing heavily. A thick ink deposit plus a heavy fabric can make a shirt stiff. If you want both, water-based print keeps the hand-feel softer.
Ignoring the market. A 280 gsm tee that sells in Northern Europe may sit unsold in a warm climate. Weight is a climate decision as much as a fashion one.
A practical way to decide
Start from your retail price and the climate you are selling into, then work back. If you are unsure, ask for a sample in two weights and hold them. Fabric weight is something you understand in seconds once it is in your hand, and not at all from a specification sheet.