You are choosing the fabric for your first custom t-shirt or hoodie. The product page says 180 GSM. Another one says 240. A third says 320. You nod, but you cannot feel a number through a screen.
Here is the short answer. 180 GSM feels like a classic everyday t-shirt. 240 GSM feels like a heavy, structured t-shirt. 320 GSM feels like a sweatshirt or hoodie, and it would feel stiff as a t-shirt. The rest of this post explains what those words mean in your hands, why the same number can feel different from one fabric to another, and how to pick the right one for your brand.
First, what GSM means
GSM stands for grams per square metre. Cut a piece of fabric that is one metre by one metre, put it on a scale, and the number is the GSM. A fabric at 180 GSM weighs 180 grams per square metre. A higher number means a heavier and usually thicker, denser fabric. A lower number means a lighter and more breathable one (Thygesen Apparel, n.d.).
The exact lab method is more careful than a kitchen scale. The sample is kept in a controlled room, a precise area is cut, and it is weighed on a precision balance. For fabric weight, textile labs follow standards such as ASTM D3776 (ASTM International, n.d.). You do not need to run that test yourself. You only need to know that GSM is a weight, and a weight is not the whole story.
180 GSM: the everyday t-shirt
At 180 GSM, a cotton t-shirt feels like the shirt most people think of when they say “t-shirt”. It is soft, it moves with the body, and it is comfortable in warm weather and in a heated room. It drapes, which means it hangs down in soft folds rather than standing away from the body.
Where you might notice its limits: light colours can be a little see-through when the fabric is stretched, and the shirt will not hold a sharp, boxy shape on its own.
It is a good match for:
- Team shirts and event shirts that need to be worn all day
- Promo shirts handed to many people
- A first drop where you want a safe, familiar feel
- Printed designs of almost any size, because the fabric is easy to print on
240 GSM: the heavy, structured t-shirt
At 240 GSM, the same cotton shirt feels different the moment you pick it up. It has body. The fabric is thicker, more opaque and a little warmer. It holds its shape at the collar and hem, and the sleeves stand away from the arm. This is the weight behind the boxy, oversized look that is popular in streetwear.
The trade-off is that it feels warmer on hot days, and it costs more to make because it uses more fabric. It is also heavier to ship, which matters if you sell online.
It is a good match for:
- A brand that wants a “premium” first feel in the hand
- Oversized and boxy cuts
- Cooler months, or layering
- Designs with a large, solid print, because a sturdy fabric holds the shape of the shirt around the print
320 GSM: sweatshirt and hoodie territory
At 320 GSM, you have left t-shirt weight. One guide puts hoodies and sweatshirts in a range of about 280 to 400 GSM and above, and French terry sweatshirts in a lower range of 220 to 350 (Thygesen Apparel, n.d.). So 320 sits comfortably inside that band.
On a hoodie it feels thick, warm and structured. The inside is often brushed, which traps air and adds warmth. On a t-shirt it would feel stiff and heavy, closer to a board than a tee, and most people would find it too warm.
It is a good match for:
- Hoodies and crewneck sweatshirts for cold weather
- Club and team wear for the colder months
- Brands that want a solid, “weighty” feel for outerwear
A quick table
| GSM | What it is usually called | What it feels like | Good for |
|---|---|---|---|
| 180 | Everyday t-shirt | Soft, light drape, breathable | Teams, events, first drops |
| 240 | Heavy t-shirt | Thick, structured, more opaque | Premium and oversized tees |
| 320 | Sweatshirt / hoodie weight | Dense, warm, firm | Hoodies and sweatshirts |
Be careful with the names, because they are not fixed. One guide calls 150 to 180 GSM “midweight” and 180 to 200 “heavyweight” (Shopify, n.d.), while another calls 160 to 200 “everyday” and 200 to 300 “heavyweight” (Thygesen Apparel, n.d.). The same 180 GSM shirt is called heavy by one and everyday by the other. This is why a number is more useful than a label, and why you should always ask for the GSM and also for a sample.
Why the same GSM can feel different
Two fabrics can both be 240 GSM and feel nothing alike. The weight only tells you how much fabric there is, not what it is made of or how it is built.
Fibre. Longer cotton fibres give a smoother, stronger and more even yarn. Short, low-grade fibres can be spun into a heavy fabric that still feels rough and pills early (SANVT, n.d.). Different fibres also feel different at the same weight. One guide notes that wool feels warmer than cotton, and linen cooler, at the same GSM, and so you should compare GSM only inside the same type of fabric (Thygesen Apparel, n.d.).
Yarn. Tighter, more even spinning helps a fabric keep its shape after many washes (SANVT, n.d.).
Knit structure. A flat jersey, a loopback French terry and a brushed fleece can all be the same weight and feel very different. The best structure depends on the garment: jersey for t-shirts, loopback or fleece for sweatshirts (SANVT, n.d.).
Finishing. Washing, brushing and softening change how the fabric feels in the hand. They can also change the weight. Natural fibres can shrink and become more compact after washing, which raises the GSM, while some finishes wash out and lower it (Thygesen Apparel, n.d.).
That last point is practical. Ask your factory whether the GSM you were quoted was measured before or after washing, and what the tolerance is. One source suggests a tolerance of around 5% either way (Thygesen Apparel, n.d.).
Heavier is not the same as better
It is easy to think that a bigger number means higher quality. It does not. As one fabric maker puts it, GSM “tells you nothing about what that material actually is”, and a poorly spun yarn stays poor at any weight (SANVT, n.d.). A heavy fabric can also hide weak materials, because thickness feels solid in the first minute of handling.
Heavier garments also put more stress on seams, so stitching and finishing matter more, not less (SANVT, n.d.). A 320 GSM hoodie with weak seams will fail before a good 180 GSM tee.
How to pick, in four questions
- When will it be worn? Hot climate or all-day wear points to a lighter fabric. Cooler weather or layering points to a heavier one.
- What look do you want? Soft and fitted usually points to 180. Boxy and structured usually points to 240 and above.
- How will the design be applied? Screen print and DTF can work on a wide range of weights. For embroidery, thin jersey can pucker, so ask for a test. Our guide to screen print, DTF and embroidery goes through this in detail.
- What does your budget allow? More fabric means more cost, and heavier garments also cost more to ship. We explain the cost layers in what really sets the price of a custom t-shirt.
Do not choose from a number alone
A number on a page cannot tell you how a fabric hangs, stretches back, or feels against the skin. That is what a sample is for. Hold it, fold it, stretch it, hold it up to a window to check how see-through it is, and wash it once.
When you place the order, write the fabric details into your tech pack: fibre, GSM with its tolerance, knit type and finishing. Here is a checklist: what a tech pack should include.
Quick questions people ask about this
What does GSM mean on a t-shirt? GSM means grams per square metre. It is the weight of one square metre of the fabric. A higher number usually means a thicker and heavier fabric.
What GSM is best for a custom t-shirt? For an everyday shirt, many brands choose around 160 to 200 GSM. For a heavier, more structured shirt, many choose 200 GSM and above. The names for these ranges differ from one source to another, so ask for the number and a sample.
What GSM is a hoodie? Hoodies and sweatshirts are often in the range of about 280 to 400 GSM and above. French terry sweatshirts are often lighter, around 220 to 350 GSM (Thygesen Apparel, n.d.).
Does a higher GSM mean better quality? No. GSM measures weight only. Fibre, yarn, knit structure and finishing matter as much, and a heavy fabric can still be poor quality.
Can GSM change after washing? Yes. Fabrics can shrink and become denser, and some finishes wash out. Ask your factory whether the GSM is measured before or after washing, and what the tolerance is.
Sources
- Thygesen Apparel (n.d.). What is GSM in fabric and why does it matter? https://thygesenapparel.com/blog/what-is-gsm-in-fabric
- SANVT (n.d.). Why heavyweight does not automatically mean quality. https://sanvt.com/blogs/journal/why-heavyweight-does-not-automatically-mean-quality
- Shopify (n.d.). How much does a shirt weigh? https://www.shopify.com/blog/how-much-does-shirt-weigh
- ASTM International. ASTM D3776/D3776M, Standard test methods for mass per unit area (weight) of fabric. https://store.astm.org/d3776_d3776m-09ar13.html
Note
GSM ranges and names vary between sources, and descriptions of how a fabric “feels” are general. Always confirm the exact fabric, weight and tolerance with your factory, and check a physical sample before you place an order.
