What GSM Should Activewear Be?

The short answer: most activewear sits between 180 and 250 g/m². Across the 109 HIVOLT garments that publish a fabric weight, the median is 220 g/m² and the full range runs from 91 to 380. Below roughly 180 you are buying breathability and accepting some transparency under stretch. Above roughly 300 you are buying structure and accepting heat.

Why the number is worth knowing

Grams per square metre is the mass of one square metre of the knit — how much fabric is actually there. It is the closest thing activewear has to a spec sheet, and it governs the three things people actually complain about: whether a legging stays opaque at the bottom of a deep squat, whether a tee clings once it is wet, and whether a hoodie holds its shape after a season of washes.

Almost no brand publishes it. “Buttery soft”, “performance knit” and “second-skin feel” are not measurements. g/m² is.

What 109 published figures actually look like

This is not an industry survey and we are not going to present it as one. It is a single catalogue: every HIVOLT garment carrying a fabric weight from its mill specification, with nothing estimated, converted from another unit, or rounded. Some categories are small — the garment count sits next to each row so you can weigh the median accordingly.

Category	Garments	Range (g/m²)	Median
T-shirts	30	91–255	177
Sports bras	17	200–270	220
Tank tops	13	180–320	220
Shorts	12	120–240	195
Leggings	9	200–270	220
Training pants	5	140–240	220
Jackets	4	230–380	305
Skirts	4	220–320	220
Hoodies	3	240–320	320
All garments	109	91–380	220

The pattern is the useful part. Tops span the widest range because a summer tee and a winter tank are doing opposite jobs. Everything worn under load — bras, leggings, tanks — converges on 220, which is not a coincidence: it is roughly where a stretch knit stops going sheer when you pull it in two directions at once.

How to read a weight before you buy

Under 150 g/m² — hot weather, and you will see through it

Summer tees and running shorts live here. Genuinely cooler to train in, and genuinely thin. Fine for a shirt, a bad idea for anything that stretches over skin.

150–199 — everyday training weight

Moves more than it holds. Most technical t-shirts sit here; our t-shirt median is 177. Comfortable, unremarkable, and the right call for a garment that is not under tension.

200–249 — where opacity stops being a gamble

The band almost every legging and sports bra we publish falls into. Enough fabric to stay opaque through a full-depth squat without the stiffness that comes later.

250–299 — compression, and cold sessions

Noticeably more hold. You feel it as support rather than as thickness, and you feel it as heat once the room warms up.

300+ — outerwear and fleece-backed layers

Structure you can feel. Hoodies and jackets, and nothing you want to be wearing at rep eight.

Where the number stops mattering

Fabric weight is one variable and pretending otherwise would be its own kind of marketing. Three things move opacity and feel independently of it:

• Elastane content. A 220 g/m² knit at 25% spandex behaves nothing like a 220 g/m² knit at 11%. More stretch means the same mass gets pulled thinner under load.
• Colour. Black hides at a weight where light grey and white do not. A 200 g/m² black legging can outperform a 230 g/m² pale one on the only test that matters.
• Knit structure. A tight interlock and an open jersey at the same weight breathe and drape differently.

Use g/m² to rule things out, not to rank them. A brand that will not tell you the number is telling you something; a brand that tells you only the number is doing the same thing more quietly.

Every figure, in one table

All 109 weights are published together in the HIVOLT Fabric Weight Index — sorted heaviest first, each linking to the garment, alongside its fibre composition. Four products in the range publish no weight at all, and they are listed there as well rather than quietly left out.

FAQ

What GSM is best for leggings?

200 g/m² and up. Every legging we publish falls between 200 and 270, with a median of 220. Below 200 a stretch knit starts showing skin at the bottom of a squat, and no waistband design fixes that.

What GSM is squat-proof?

There is no single threshold, because opacity depends on weight, colour and elastane together. As a working rule: 220 g/m² or heavier in black, and closer to 250 in a light colour. Then run the actual test — deepest squat, bright light, look in a mirror.

Is a heavier fabric always better?

No. Heavier means more opaque, more supportive and hotter. For a summer running tee that is a downgrade, not an upgrade. Match the weight to the session.

What GSM should a workout t-shirt be?

130–180 g/m² for hot-weather and high-sweat training, 180–220 if you want it to hang rather than cling. Our t-shirts run 91 to 255 with a median of 177.

Why do so few brands publish GSM?

Because it is a commitment. A published number can be checked, compared against a competitor, and held against you when a garment underperforms. Adjectives cannot.