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Understanding fabric weight: a buyer’s guide to GSM in woven garments

If you only learn one fabric spec before developing a woven program, make it GSM. It tells you more about how a shirt or dress will look, feel, drape and wear than almost any other single number — and it’s the spec most often left vague on a tech pack.

What GSM actually means

GSM stands for grams per square metre — the weight of one square metre of a fabric. A poplin at 110 GSM is light and crisp; a twill at 280 GSM is substantial and structured. Because it’s a weight per fixed area, GSM lets you compare two fabrics fairly even when their construction, yarn and weave are different.

It’s a more reliable signal than thread count, which can be inflated by counting plied yarns twice and says little about hand or durability. Two fabrics with the same thread count can feel completely different; their GSM usually won’t lie.

Typical weight ranges for woven garments

These are working ranges we use for shirting, dresses and bottoms. They’re guides, not rules — finish, weave and fibre all shift how a given weight behaves.

Why the same GSM can feel different

Weight is the headline, but three things change how it reads on the body:

• Weave. A 150 GSM poplin feels crisper than a 150 GSM twill of the same yarn, because the weave changes drape and surface.
• Fibre. Linen and viscose hang heavier and softer than cotton at the same weight; a polyester blend feels firmer.
• Finish. Enzyme washing, peaching and calendering all alter the hand without changing GSM much — so always judge a finished, washed swatch, not greige cloth.

Specify a GSM and a tolerance. “160 GSM ± 5%” removes the single most common source of bulk-vs-sample disappointment.

How to choose the right weight

Work backwards from the garment’s job:

• Market & climate. A shirt for a Gulf summer wants 110–130 GSM; the same style for European autumn might sit at 150–170.
• Price point. Heavier cloth uses more yarn and usually costs more per metre — weight is a real lever on landed cost, not just feel.
• Construction. Lighter fabrics demand cleaner sewing; faults hide in heavier, textured cloth. Match your weight to the finishing standard you can hold.
• Drape vs structure. Decide whether the style should flow or hold a shape, then pick the weight that gets you there — and confirm it on a sewn sample, not a swatch.

What to put on your tech pack

For every woven style, we ask buyers to lock four things up front: GSM with tolerance, weave (poplin, twill, dobby, oxford…), fibre composition, and the finish. With those four fixed, sampling moves faster and bulk matches the approved sample far more reliably.