Quick answer: GSM stands for grams per square metre. It measures how much a piece of fabric weighs, which makes it a quick read on how thick and substantial a hoodie or tee will feel. As a rough guide, hoodies under 280 GSM are lightweight, 280 to 350 is midweight, and 350 and up is heavyweight.
What does GSM actually mean?
Take one square metre of fabric and weigh it. That's the number. A 400 GSM fleece weighs 400 grams per square metre, and a 180 GSM tee jersey weighs 180. More grams usually means more yarn packed into the same space, so the fabric feels thicker, drapes heavier and holds its shape instead of clinging to you.
It's also one of the few numbers on a product page that's hard to fudge. Words like "premium" and "luxe" cost nothing to write. GSM gets measured.
Nerd corner: Factories check GSM with a tool called a GSM cutter, which punches out a perfect circle of fabric exactly 100 square centimetres in size. Weigh the circle, multiply by 100, and you've got the GSM. That little disc is basically a quality receipt.
What GSM is good for a hoodie?
| Weight class | Hoodie GSM | Tee GSM | How it feels |
|---|---|---|---|
| Lightweight | Under 280 | Under 150 | Thin and drapey. Good for layering or warmer days. |
| Midweight | 280 to 350 | 150 to 200 | The everyday all-rounder, with some structure. |
| Heavyweight | 350 and up | 200 and up | Thick and structured. Holds a boxy shape. |
These are industry rules of thumb, not an official standard, and brands draw the lines in slightly different places. So check the actual number rather than trusting a label that just says "heavyweight".
What GSM is best for a t-shirt?
Tees run lighter than hoodies because they're a single layer of jersey. Under about 150 GSM, a tee is thin and can turn see-through in white or pale colours. Between 150 and 200 you're in everyday territory. Past 200 GSM you're into heavyweight tees, the boxy, structured kind streetwear lives in. They keep their shape, don't cling, and generally survive more washes. The trade-off is warmth, which you'll notice on a 35 degree January afternoon.
What GSM hoodie do you actually need in Australia?
A lot of the heavyweight hype comes from US and European streetwear, built for northern hemisphere winters where 450 to 500 GSM makes sense. Melbourne winter days often top out in the low to mid teens, and Sydney and Brisbane are milder again. For everyday wear here, a midweight to lower heavyweight hoodie is often the sweet spot. Go heavier if you run cold, want that structured, oversized drape, or live somewhere that gets a proper winter.
Then there's the classic four seasons in one day. A mid to heavy hoodie over a tee handles a 9 degree morning and a 19 degree arvo far better than a sleeping bag with sleeves.
Is a higher GSM always better quality?
No. GSM tells you about weight, not quality. A heavy hoodie spun from short, rough fibres can still pill, twist and lose its shape. A midweight made from combed, ring-spun cotton can outlast it. Fibre quality, yarn type, knit and construction all do serious lifting too. Our guide to cotton terms breaks down what to look for.
Heavier fabric is also warmer, slower to dry and more expensive to make. The right GSM is the one that suits how and where you actually wear it.
How do you check GSM when shopping online?
Look in the product description or the specs section. If a brand won't tell you the GSM, that's information too, because brands that are proud of their fabric usually say so. While you're there, check the composition (100 per cent cotton or a blend) and the fabric type, such as French terry or brushed fleece.
FAQs
Is 400 GSM good for a hoodie?
Yes. 400 GSM is heavyweight: thick, warm and structured. It's great for cold days and boxy fits, but it can feel like a lot on a mild Australian day.
Is 300 GSM a heavyweight hoodie?
Generally no. 300 GSM sits in the midweight range. Some brands call it heavyweight, but most rules of thumb start heavyweight at around 350 GSM.
What does 240 GSM mean on a t-shirt?
It means a heavyweight tee. It's noticeably thicker than a standard tee, holds its shape better and is less likely to be see-through.
Does a higher GSM mean less pilling?
Not on its own. Pilling depends mostly on fibre length, yarn type and friction, so a lighter hoodie made from better yarn can pill less than a heavier one made from cheaper yarn.
Heavy when you want structure. Lighter when you want to move. Either way, now you can read the number.