What is GSM in fabric? Weight explained

Rough weights for suit fabrics

These bands are approximate. Fabrics of the same name vary from mill to mill, and the bands overlap. As a rule of thumb, a dupatta sits in the lightest band, a kameez in the middle bands according to season, and trousers do well a step heavier than the kameez, so that they stay opaque and hang straight.

• Up to about 70 GSM: very light sheers such as chiffon, organza, net and fine malmal. Dupattas, sleeves and overlays.
• About 70 to 110 GSM: light cottons such as lawn and voile, and georgette. Summer kameez, often lined in pale shades.
• About 110 to 160 GSM: cambric, poplin, light linen, cotton satin and most crepe. Kameez for milder weather, and trousers.
• About 160 to 250 GSM: khaddar, karandi, heavier linen and other winter cloths. Winter kameez and trousers.
• Above about 250 GSM: denim, heavy velvet and coat fabrics. Rare in a kameez.

What weight tells you, and what it does not

Our article on how fabric changes fit and drape shows why the same measurements look different in different weights.

• Drape: heavier cloth hangs straighter and pulls its own creases out. But stiffness is separate: organza is very light and still stands away from the body.
• Opacity: heavier usually means less see-through. But weave and colour count too. A dense, light lawn can cover better than a heavier cloth with an open weave.
• Season: lighter is usually cooler. But fibre counts for more. A light polyester can feel hotter than a heavier linen.
• Wear: heavier cloths often last longer, though a fine, tightly woven cloth can outlast a thick, loose one.

Why heavier is not automatically better

It is tempting to read GSM as a score. It is not. Fine lawn is prized for being light: it takes fine yarn and careful weaving to make a cloth that thin and still even. A higher GSM in a lawn may simply mean thicker yarn. New fabric can also carry starch or other finishes that add weight and wash out the first time.

And weight has costs. Heavy cloth is warmer, bulkier in gathers and pleats, and heavier on the shoulders in a long kameez. The right weight is the one that suits the garment and the weather, which is why a GSM figure is useful for comparing two similar fabrics and not much use for ranking different ones.

Working it out yourself

You can find the GSM of a piece of fabric with kitchen scales and a tape measure. Weigh the piece in grams, then divide by its area in square metres, which is its length in metres multiplied by its width in metres. A length of fabric 2.5 metres long and 1.1 metres wide has an area of 2.75 square metres. If it weighs 220 grams, it is 80 GSM.

Two other units turn up. American sellers often give ounces per square yard, and one ounce per square yard is about 34 GSM. Silk is traditionally weighed in momme, and one momme is a little over 4 GSM. Width is a separate matter, covered in our guide to fabric widths.

Using weight when you order

You do not need a number to order. Words such as light and airy, mid-weight and opaque, or warm and substantial tell us what you need. With Fabric + Stitching, describe the season, the garment and how covered you want to be, and we propose a fabric with photos and a description, agreed with you before cutting. If you know a GSM you like from a garment you own, mention it when you ask for a quote. Our page on choosing fabric explains how the choice is made.