Short answer
GSM — grams per square metre — is the weight of one square metre of fabric, and it is the first thing to decide when specifying a t-shirt. 180 gsm is the everyday standard, 220 gsm is mid-heavyweight with more structure and drape, and 240 gsm is heavyweight with a boxy, substantial feel. Heavier is not automatically better: it costs more, is harder to work at the machine and sells at a higher price point.
Key points
- GSM measures fabric weight, not garment weight — a large garment in lighter fabric can weigh more than a small one in heavier fabric.
- 180 gsm is the standard everyday tee. 220 gsm sits in the middle. 240 gsm is where the boxy, structured streetwear feel starts.
- Fabric type matters as much as the number: combed and ring-spun cotton behave differently from carded at the same GSM.
- Heavier fabric costs more per metre and takes longer to cut and sew, which is why unit price rises with GSM.
- Blends let you reach a target weight and handle more cheaply than 100% cotton at the same GSM.
Buyers specify GSM because it is the fastest way to describe how a garment feels before anyone has touched it. It is also the number most often quoted badly — from suppliers who do not measure it, and from buyers who treat it as the only thing that matters.
What GSM actually measures
GSM is the weight of one square metre of fabric. Note "of fabric" — it is not the weight of the finished garment.
A large garment in 130 gsm fabric can weigh more than a small garment in 240 gsm. If someone tells you a t-shirt "weighs 180 gsm" they are describing the cloth, and if they describe a finished garment as 180 gsm they are using the term wrong. It happens often enough to be worth asking directly.
The weights that matter
| GSM | Usual construction | How it wears | Typical use |
|---|---|---|---|
| 110–130 | Single jersey, light | Thin, drapes close, shows transparency under strong light | Summer basics, layering, promotional tees |
| 140–160 | Single jersey, mid | Light but opaque, soft | Fashion tees, everyday basics |
| 180 | Single jersey, standard | The everyday standard: holds shape, fully opaque, comfortable | General retail and merchandise |
| 220 | Combed or ring-spun jersey | More structure, better drape, smooth surface | Premium basics, heavier retail |
| 240 | Mid-heavyweight jersey | Boxy, substantial, holds its shape when worn | Streetwear, structured silhouettes |
| 260+ | Heavy jersey or fleece | Very substantial, almost rigid at first | Premium streetwear, outerwear-adjacent |
180 vs 220 vs 240 — the actual differences
**180 GSM** is the standard everyday t-shirt. It is opaque, it holds its shape through washing reasonably well, and it is the weight most buyers mean when they say "a normal t-shirt". It is the safest starting point if your customer has no strong preference.
**220 GSM** sits between a basic and a premium. The surface is smoother, the drape is heavier, and it holds a boxier line on the body. Buyers moving up from 180 usually do so to signal a step up in quality, and it shows in the hand-feel immediately.
**240 GSM** is where the structured streetwear look begins. It stands slightly away from the body, holds a wide silhouette without collapsing, and reads as substantial. This is the weight most associated with drop-shoulder and boxy fits. It is also the heaviest of the three to produce: it cuts and sews more slowly, and it costs more per metre.
GSM is only half the specification
Two fabrics at 180 gsm can feel completely different. The variables that matter alongside the number:
- **Yarn construction** — combed, ring-spun and carded are different processes. Ring-spun produces a smoother, stronger yarn; carded is cheaper and slightly irregular.
- **Fibre content** — 100% cotton, polyester blends and viscose blends behave differently for drape, shrinkage and wash performance.
- **Jersey type** — single jersey, pique, interlock and slub all sit at the same GSM and feel different.
- **Finish** — enzyme washing, garment dyeing and peach-finish all change the hand.
A specification that says "180 gsm" and nothing else is incomplete. "180 gsm ring-spun single jersey, 100% cotton" is a specification.
How to choose
**Choose 180 gsm** if you are selling a general retail tee, a merchandise line, or anything where price sensitivity is high.
**Choose 220 gsm** if you want a step up in perceived quality without moving to a streetwear price point.
**Choose 240 gsm or heavier** if your product is a structured, boxy or drop-shoulder silhouette and your customer expects that weight. Under-delivering on weight is the fastest way to generate returns on a heavyweight product.
Why GSM changes the price
Higher GSM means more material per metre, usually a more expensive yarn to hold that weight, and slower cutting and sewing because the cloth is stiffer at the machine. All three land in the unit cost.
If you are moving from 180 to 240 GSM, expect the unit price to rise. If a supplier quotes the same price for both, one of the two is not what they said it was.
One practical warning
Heavier fabric also drapes differently over a size range. A 240 GSM garment does not grade the way a 180 GSM one does, because the fabric resists forming to a curved seam the same way. Wide size ranges in heavyweight fabric need more attention at pattern stage than the same range in a lighter cloth. If you are specifying heavy fabric across many sizes, raise it early.
Where to go next
Frequently asked questions
What does GSM stand for?
Grams per square metre. It is the weight of a one-square-metre sample of the fabric. Because it is measured per area rather than per garment, the same GSM fabric can produce garments of very different weights depending on size.
Is 240 GSM too heavy for a t-shirt?
It is heavy, but not unusually so — that is the standard weight for a structured, boxy t-shirt in streetwear. What matters is the market you are selling into and the price you can support. It is the wrong choice for a summer basic.
Does GSM affect durability?
It affects how the garment handles wear and washing, mainly because heavier fabric resists distortion and abrasion better. Durability is more determined by construction and fibre content, but GSM is part of the picture.
Can I get 240 GSM in a blend?
Yes. Polyester and cotton blends are commonly produced at heavier weights and are easier to wash, quicker to dry and usually cheaper than 100% cotton at the same GSM.
Why does the fabric cost more at higher GSM?
You are buying more material per metre and usually a more expensive yarn construction to hold that weight. It also cuts and sews more slowly because the fabric is stiffer, which shows up in labour time.