GSM stands for grams per square meter: the weight of a one-square-meter swatch of the fabric, measured before anything is sewn. On t-shirts, 120 to 150 GSM is a thin promotional blank, 150 to 180 is a light summer tee, 180 to 220 is the standard everyday range, and 220 and up counts as heavyweight. XISVEL prints on a 280 GSM knit. The chart, the ounce conversion, and what the number controls are below.
What does GSM stand for?
Grams per square meter. A mill cuts a square meter of the knit fabric and weighs it; that weight in grams is the GSM. A 180 GSM fabric weighs 180 grams per square meter, a 280 GSM fabric weighs 280. Because the measurement happens on the raw fabric, the same number applies to every size of the finished shirt: a small and a 3XL cut from the same roll are both 280 GSM shirts.
Most of the world specs fabric in GSM. American mills and brands more often use ounces per square yard, which converts cleanly in both directions; the math has its own section below.
T-shirt GSM chart
These are the ranges the apparel industry quotes. Feel still varies with fiber and knit, but each step up buys structure and opacity, and each step down buys coolness and out-of-the-package softness:
| GSM | oz per sq yd | What it feels like | Where you meet it |
|---|---|---|---|
| 120–150 | 3.5–4.4 | Thin, slightly sheer, very soft | Promotional and event tees, multipacks |
| 150–180 | 4.4–5.3 | Light, airy, softens fast | Summer tees, budget fashion blanks |
| 180–220 | 5.3–6.5 | The familiar standard tee weight | Everyday retail t-shirts |
| 220–260 | 6.5–7.7 | Dense, structured, holds its shape | Premium fashion tees, workwear-inspired cuts |
| 260–300 | 7.7–8.8 | Heavy, opaque, drapes with weight | Heavyweight streetwear tees; XISVEL's 280 GSM sits here |
Ounces are rounded to one decimal. For reference, every XISVEL zodiac tee is knit at 280 GSM (the bold row above).
Is a higher GSM better?
No, and the number alone never settles it. GSM measures how densely the fabric is knit. Quality lives in the fiber and the yarn: a well-combed 200 GSM cotton beats a carded, short-staple 240 GSM on smoothness, pilling, and wash survival. Two shirts at the same weight can differ more than two shirts 60 GSM apart.
What a higher GSM reliably buys is physical. Heavier knits are more opaque (white tees stop going see-through under light), hold their shape and drape instead of clinging, take a deep print without the ink distorting, and shrink and twist less over a long life. The cost is real too: a heavyweight tee runs warmer, dries slower, and starts stiffer until the first few washes relax it.
What GSM should a t-shirt be?
Match the weight to the job. A July shirt you sweat in is best at 150 to 180. An everyday shirt that has to survive a hundred washes sits well at 180 to 220. Dark graphic prints and streetwear cuts benefit from 240 and up, where the fabric is opaque enough that the shirt itself disappears under the artwork. That last range is where XISVEL works: a dense gothic or constellation print on a 280 GSM black knit reads crisp in person and in photos, and the shirt keeps its shape long after the print has been through a hundred wash cycles. The wash-by-wash comparison between weight classes is tracked in our heavyweight vs. standard cotton explainer.
How does GSM affect the print?
Printing is where fabric weight pays off fastest. A heavyweight knit is a stable base: it resists the stretch distortion that slowly pulls a front-chest print out of shape, and it holds dense coverage, large solid areas, and fine gothic linework without the fabric showing through the ink. Thin blanks can take the same art and age worse; the print cracks along the fold lines first, and the fabric under a large print yellows at a different rate than the rest of the shirt. A shirt that exists to carry artwork belongs on weight.
How do you convert GSM to ounces?
One ounce per square yard equals 33.9 grams per square meter. Divide GSM by 33.9 to get ounces:
| GSM | oz per sq yd |
|---|---|
| 150 | 4.4 |
| 180 | 5.3 |
| 200 | 5.9 |
| 220 | 6.5 |
| 240 | 7.1 |
| 280 | 8.3 |
Tags and spec sheets round differently from each other, so a shirt listed as 8 oz in one place and 220 GSM in another may be the same fabric. When two numbers disagree by more than about ten percent, one of them is rounding or quoting a different measurement.
What are XISVEL tees made of?
The spec, exactly as it ships: a 280 GSM knit in two fits. The Regular fit is 73.7% combed cotton with 26.3% Sorona, a stretch fiber that adds softness and helps the shirt hold its shape; the Oversized fit is 100% combed cotton. Combed cotton has had the short fibers combed out before spinning, which is why it feels smoother and pills less than carded cotton at the same weight. Every design in the zodiac collection is printed on this same base, so weight and hand feel stay consistent across all twelve signs. A typical example is the "Scorpio" Zodiac Graphic Tee, whose oversized gothic back print shows what the 280 GSM knit does for dense artwork.
Frequently asked questions
What does GSM mean on a t-shirt?
Grams per square meter: the weight of one square meter of the shirt's fabric. Higher numbers mean denser, heavier fabric.
What is a good GSM for a t-shirt?
180 to 220 for an everyday tee, 150 to 180 for hot-weather wear, 240 and up for heavyweight graphic tees. XISVEL tees are 280 GSM.
How many ounces is 280 GSM?
About 8.3 ounces per square yard. Divide any GSM figure by 33.9 to convert.
Is 280 GSM too heavy for summer?
It is a spring-to-fall weight in hot climates and a year-round weight in mild ones. Heavyweight knits breathe less than light ones; that is the trade for opacity, drape, and print life.