GSM is the number on almost every T-shirt listing in India, and the one most people scroll past. So what is GSM in a T-shirt, and what does it tell you about how a tee will feel, hang and cope with a Delhi May afternoon or an over-air-conditioned office in Bengaluru?
This guide covers what the number means, our full GSM chart, honest comparisons between weights, what French terry actually is, how hoodies differ at 300 and 400 GSM, and how to look after the print. It's the guide we'd want before buying.
What does GSM mean on a T-shirt?
GSM stands for grams per square metre. It's the weight of one square metre of the fabric a garment is cut from, so it describes how dense the fabric is, not how much the finished tee weighs. A 180 GSM tee is cut from fabric that weighs 180 grams per square metre; 240 GSM fabric is heavier and denser.
In practice, a higher GSM usually means a thicker fabric that feels more substantial, is less see-through and holds its shape better. A lower GSM usually means a lighter fabric that feels airier and dries faster.
GSM is not thread count. Thread count measures how many threads are woven into a square inch, and it's used for woven fabrics such as bedsheets. T-shirts and hoodies are knitted, so weight per area is the useful number.
If you shop from international brands, you'll also see ounces per square yard. One ounce per square yard is about 33.9 GSM, so a 180 GSM tee is roughly 5.3 oz, 240 GSM is about 7.1 oz and 400 GSM is about 11.8 oz.
Our GSM chart: every FDC fit in one table
Fourth Dimension Club tees and hoodies range from 180 to 400 GSM. Our regular half-sleeve tee is 180 GSM, the classic oversized tee is 240, the French terry oversized tee is 260, the regular hoodie and crew sweatshirt are 300, and the heavyweight oversized hoodie is 400.
These specs are for our India store, thefourthdimension.club.
| Product | GSM | Fabric | Feel | Best for |
|---|---|---|---|---|
| 180 GSM half-sleeve T-shirts | 180 | 100% cotton (melange colours 90% cotton / 10% polyester) | Light, soft, classic | Daily wear, peak summer, layering under shirts |
| 240 GSM oversized T-shirts | 240 | 100% cotton, drop shoulder | Substantial, smooth, holds a boxy shape | Oversized looks year-round |
| 260 GSM French terry oversized tees | 260 | 90% cotton / 10% polyester French terry, drop shoulder, lycra ribbed neck | Smooth outside, soft looped inside, a little warmer | AC offices, evenings, travel, cooler months |
| Crew sweatshirt | 300 | 90% cotton / 10% polyester brushed fleece, derby rib hem and cuffs | Soft and fuzzy inside | Winter mornings, layering |
| 300 GSM hoodies | 300 | 90% cotton / 10% polyester, derby rib | Everyday hoodie weight | Everyday winter wear, layering |
| 400 GSM heavyweight oversized hoodies | 400 | 90% cotton / 10% polyester, drop shoulder, derby rib | Thick, structured, warm | Proper winters, hill trips, statement layering |
Two details worth knowing. Our melange (heathered) colours in the 180 GSM tee are a 90/10 cotton-polyester blend, not 100% cotton. And the 260 GSM French terry is a 90/10 blend too, which is normal for terry and fleece.
180 vs 240 GSM: which should you buy?
Choose by cut and season, not by the bigger number. A 180 GSM tee is the better everyday tee for peak summer: lighter, quicker to dry and cut in a regular fit. A 240 GSM tee suits an oversized, drop-shoulder cut, because the heavier fabric holds that boxy shape and is more opaque, especially in light colours.
Think about where you'll wear it. For a May commute in Delhi or a humid Mumbai monsoon day, the lighter 180 GSM tee is the one you'll reach for. It also sits neatly under an open shirt or a jacket without adding bulk.
The 240 GSM tee earns its weight in an oversized cut. Heavier fabric drapes away from the body instead of clinging, and in white or pastel colours it's noticeably less see-through.
If you want one of each, the honest split is a 180 for the hottest months and a 240 for everything else.
What GSM is best for an oversized T-shirt?
For an oversized T-shirt, around 240 GSM and up works best. Heavier fabric falls in a straight line from the dropped shoulder instead of clinging, which is what makes oversized look intentional rather than just big. We make oversized tees in 240 GSM cotton and 260 GSM French terry.
Light fabric in a big cut tends to collapse and stick to the body, especially in humidity. The extra weight gives the tee enough body to keep its boxy outline when you move.
Between our two oversized options, the 240 GSM cotton tee is the all-rounder for hot days. The 260 GSM French terry tee has a looped inside, so it feels softer against the skin, a touch warmer and a little more structured.
What is French terry?
French terry is a knitted fabric with a smooth, flat face on the outside and small loops of yarn on the inside. It's in the same family as sweatshirt fabric, but the loops are left unbrushed, so it's less fuzzy than fleece. Our French terry tees are 260 GSM, 90% cotton and 10% polyester, with a lycra ribbed neck.
It isn't towel fabric. Terry towelling usually has loops on both sides, built to soak up water. French terry has loops on one side only, facing your skin, and because it's knitted, it stretches and drapes like a tee should.
Fleece is the next step along. Brush those inside loops until they turn fuzzy and you get fleece, which is what our crew sweatshirts use. That's why fleece feels warmer and softer than French terry at a similar weight.
The smooth outer face is also a good surface for a print. Our Strange Signals UFO tees are a good example of what 260 GSM French terry looks like with a full-colour design on it.
Our French terry tees are oversized with dropped shoulders. Check the French terry size chart before you order: take your usual size for the full oversized look, or size down for a closer fit.
French terry vs cotton jersey for Indian weather
Pick cotton jersey for hot afternoons, long commutes and humid days, and French terry for AC offices, evenings, travel and the cooler months. French terry is warmer and takes longer to dry because of its looped back, so it isn't the tee for a Chennai afternoon in May.
| Cotton jersey (our 180 and 240 GSM tees) | French terry (our 260 GSM tees) | |
|---|---|---|
| Structure | Smooth single knit | Smooth face, looped inside |
| Feel | Light and familiar | Softer inside, more substance |
| Warmth | Cooler | Warmer |
| Drying time | Faster | Slower |
| Best for | Summer days, humid weather, long commutes | AC offices, evenings, flights and train journeys, winter |
The trade-off is real and worth being honest about. If you sweat on your commute, a looped fabric holds on to that moisture longer. If you spend the day in a cold office or travel overnight, the same loops make French terry the more comfortable choice.
Across much of India, that makes French terry a strong pick from October to February and for indoor days the rest of the year.
Hoodies and sweatshirts: 300 vs 400 GSM
300 GSM is the everyday hoodie weight: warm enough for winter mornings, light enough to layer. Our regular hoodie and crew sweatshirt are both 300 GSM. 400 GSM is heavyweight: thick, structured and warm, built for real winters. That's our heavyweight oversized hoodie, with dropped shoulders and derby rib.
Choose 300 GSM if your winter means cool mornings and evenings, as in Bengaluru or Pune, or if you want something to throw over a tee in an AC office. The crew sweatshirt is brushed fleece inside, so it feels soft and cosy without the bulk of a heavyweight.
Choose 400 GSM if you face a proper north Indian winter, a hill trip in December or a long night outdoors. It's heavy by design: the weight gives it a structured, boxy drape that reads as a statement piece.
One thing to be clear about: the 400 GSM hoodie is not French terry. It's a 90/10 cotton-polyester heavyweight with derby rib cuffs and hem.
Is higher GSM always better quality?
No. GSM tells you how heavy the fabric is, not how good it is. Fibre quality, the knit, the stitching, the print and the fit matter just as much. A well-made 180 GSM tee is the better choice for a summer day, and a 400 GSM hoodie is the wrong choice for a Mumbai October.
Heavier fabric is often sold as automatically "better", but weight only tells you one thing. A dense but poorly finished fabric can still feel rough or twist out of shape, while a light, well-knitted cotton can feel better than a heavier one.
The better question is "which weight suits this cut and this weather?" Use GSM to narrow your choice, then look at the fibre, the fit and when you'll actually wear it.
Care tips that protect the print
Machine wash cold, inside out, with a mild detergent. Don't iron or scrub directly on the print, and skip bleach and the tumble dryer. It's the same care routine on every product page, and it works for every weight from 180 to 400 GSM.
Turning the garment inside out protects the print from rubbing against other clothes in the drum. Cold water is kinder to both the print and the fabric.
Heavier pieces hold more water, so give French terry tees and hoodies extra drying time before you fold them away.
Frequently asked questions
What does GSM mean in a T-shirt?
GSM means grams per square metre. It's the weight of one square metre of the tee's fabric, so it tells you how dense and heavy the fabric is, not the weight of the finished T-shirt. A higher number usually means a thicker, more opaque fabric; a lower number means a lighter, airier one.
Is 180 GSM or 240 GSM better?
Neither is better overall; it depends on the cut and the season. 180 GSM suits regular-fit tees for hot weather and daily wear. 240 GSM suits oversized, drop-shoulder tees, because the heavier fabric holds the boxy shape and is more opaque, especially in white and pastel colours.
What is the best GSM for an oversized T-shirt?
Around 240 GSM and above. Heavier fabric drapes in a straight line from the dropped shoulder instead of clinging, which makes an oversized fit look intentional rather than just big. Our oversized tees come in 240 GSM cotton for everyday wear and 260 GSM French terry for a softer, slightly warmer feel.
What is French terry fabric, and is it good for T-shirts?
French terry is a knit with a smooth outer face and small loops on the inside. It's good for T-shirts you'll wear in AC spaces, evenings or cooler months, because it feels soft, holds an oversized shape and takes prints well. Ours is 260 GSM, 90% cotton and 10% polyester.
Is French terry hot in Indian summers?
It's warmer than cotton jersey and dries more slowly, so it isn't ideal for hot, humid afternoons outdoors or a sweaty commute. It works best in AC offices, in the evenings, on flights and train journeys, and in the cooler months, roughly October to February across much of India.
Is a 400 GSM hoodie too heavy?
It's heavy by design: thick, structured and warm, made for proper north Indian winters, hill trips and long nights outdoors. If you want a hoodie for layering, cool mornings or milder winters like Bengaluru's or Pune's, choose a 300 GSM hoodie or crew sweatshirt instead.
Does higher GSM mean better quality?
Not on its own. GSM measures fabric weight, not quality. Quality also depends on the fibre, the knit, the stitching, the print and the fit, and the right weight depends on the cut and the weather. A well-made 180 GSM tee beats a 400 GSM hoodie on a summer afternoon.
What GSM are Fourth Dimension Club tees and hoodies?
On our India store, regular half-sleeve tees are 180 GSM, classic oversized tees are 240 GSM, French terry oversized tees are 260 GSM, regular hoodies and crew sweatshirts are 300 GSM, and heavyweight oversized hoodies are 400 GSM. The French terry tees, hoodies and sweatshirts are 90% cotton and 10% polyester.
Sources
- ASTM D3776, Standard Test Methods for Mass Per Unit Area (Weight) of Fabric: https://www.astm.org/d3776_d3776m-20.html
Start with the fit you'll wear most, then use the chart above to pick your weight.
