If you have shopped for a heavyweight hoodie or a boxy tee lately, you have probably seen numbers like 230 GSM, 350 GSM or 440 g/m² in the product details. That number tells you more about how a piece will look, feel and wear than almost anything else on the page. Here is what it means and how to use it.
What does GSM mean?
GSM stands for grams per square meter (you will also see it written as g/m²). It is the weight of one square meter of the fabric. The higher the number, the more material is packed into the same area, so the fabric is usually thicker, denser and warmer.
Some brands, especially in the US, list fabric weight in ounces per square yard instead. To convert, divide GSM by about 34 (the exact figure is 33.9). So 350 GSM is roughly 10.3 oz, and 470 GSM denim is roughly 13.9 oz.
What counts as heavyweight?
There is no official standard, and every brand draws the lines a little differently, but these are common rules of thumb:
| T-shirts | Hoodies & sweatshirts | |
|---|---|---|
| Lightweight | Under about 160 GSM | Under about 280 GSM |
| Midweight | About 160–200 GSM | About 280–350 GSM |
| Heavyweight | About 200–250 GSM | About 350–400 GSM |
| Ultra heavyweight | 250 GSM and up | 400 GSM and up |
Most basic, multipack tees sit toward the light end of that scale. Streetwear brands lean heavier because a denser fabric holds a boxy, oversized shape instead of collapsing against the body.
What a higher GSM changes
- Structure and drape. Heavier fabric stands away from the body, so boxy and drop-shoulder fits keep their shape. Lighter fabric drapes and clings more.
- Warmth. More fabric traps more air. A 400+ GSM hoodie can work as a light jacket in autumn.
- Opacity. Heavier tees are less see-through, which matters most for white and light colors.
- Feel over time. A dense knit tends to feel more substantial and hold its shape through repeated washing.
The trade-off: heavier pieces are warmer and less breathable, take longer to dry and can feel stiff at first. A 280 GSM tee is great for most of the year, but on a very hot day a lighter one may be more comfortable.
GSM is not the whole story
Two garments with the same GSM can feel very different. When you compare, also look at:
- Fiber. 100% cotton feels soft and breathes well. Cotton-polyester blends are common in fleece because polyester helps the fabric keep its shape and color; a little spandex adds stretch.
- Knit and finish. Brushed fleece has a soft, fuzzy inside and feels warmer. Washed or vintage finishes soften the fabric and give it a worn-in look.
- Pre-shrinking. Pre-shrunk fabric keeps its size better after the first wash, which matters for fitted measurements.
- Cut. A boxy, drop-shoulder cut shows off a heavy fabric; a slim cut in the same fabric will feel bulkier.
How to choose the right weight
Everyday tees: 200–250 GSM
A solid everyday weight that still breathes in warm weather. Our 230 GSM Boxy Fit Cotton T-Shirt is 100% cotton with a loose, boxy cut.
Structured tees: 250 GSM and up
If you want a tee that keeps a clean, boxy shape on its own, go heavier. The Ultra Heavyweight 280 GSM Boxy T-Shirt is pre-shrunk 100% combed cotton with taped neck and shoulders.
Spring and autumn hoodies: 340–360 GSM
Warm enough to wear on its own on cool days, light enough to layer. Try the 350 GSM Boxy Piping Fleece Hoodie, the Butterfly Full Zip Boxy Hoodie (350 gsm) or the Sunfade Two-Way Zipper Hoodie (355 gsm).
Cold-weather hoodies: 380 GSM and up
For real warmth and the most structure, look above 380 GSM: the Heavyweight Crewneck Sweatshirt (380 g/m² brushed fleece), the High Neck Zip-Up Hoodie (400 gsm), the Washed Zip-Up Fleece Hoodie (410 gsm) and our graphic hoodies in 440 g/m² cotton.
Caring for heavyweight pieces
- Wash inside out, in cold or cool water, on a gentle cycle.
- Skip bleach, and wash with similar colors, especially for washed and vintage finishes.
- Tumble dry low or hang dry. High heat is the main cause of shrinking and fading.
- Heavy fabric holds water, so give it extra time to dry fully before you put it away.
Every VFF product page lists the exact fabric weight, composition and care instructions.
FAQ
Is a higher GSM always better?
No. Higher GSM means heavier and usually warmer, not automatically better. Pick the weight that suits the season and the look you want.
Is 350 GSM a heavyweight hoodie?
Yes, 350 GSM is generally considered the start of heavyweight for hoodies. Anything above 400 GSM is very thick.
What GSM is a good heavyweight t-shirt?
Around 220–250 GSM feels noticeably heavier than a basic tee; 280 GSM and above feels dense and structured.
Ready to shop by weight? Browse our heavyweight essentials, hoodies & sweatshirts and T-shirts & tops.