GSM stands for grams per square metre and is the standard measure of fabric weight on most Indian mill specifications. As a guide, light shirting usually sits around 100 to 140 GSM, mid-weight bottom-weight fabrics for trousers and chinos run roughly 200 to 300 GSM, and canvas and heavy drill go above that. The right weight depends on the garment, the season and the market, not on which number sounds better. Settling it properly at the specification stage avoids most of the later arguments about hand feel and durability.
Typical weight bands
- Voile, lawn and fine shirting: usually below 120 GSM, for summer tops, blouses and linings.
- Standard shirting such as poplin and oxford: roughly 100 to 160 GSM.
- Light bottom weights and twills for chinos and skirts: around 180 to 240 GSM.
- Heavier drills for workwear and uniforms: roughly 250 to 350 GSM.
- Canvas, duck and upholstery cloth: usually above 300 GSM, and often quoted in ounces per square yard instead.
How GSM is measured and why it drifts
A GSM cutter punches a circular swatch of known area, usually 100 square centimetres, and the swatch is weighed on a balance. Multiplying the weight in grams by 100 gives the GSM. ISO 3801 and ASTM D3776 cover the method, and both call for the sample to be conditioned first, because cotton picks up moisture and a damp swatch weighs more.
The figure changes through processing. Greige fabric is lighter than finished fabric because the cloth shrinks in width and length during wet processing, and finishes such as resin or softener add weight of their own. For this reason the contract should state finished GSM, the tolerance and the test method, and the mill's quoted figure should be checked on finished cloth rather than on loom-state fabric.
Choosing the weight for your product
Start from the garment and the customer. A work shirt for a cold market wants more weight than a resort shirt, and a tote bag needs a cloth that holds its shape without a lining. Weight also moves cost: more grams per metre means more cotton, so a heavier specification is usually dearer per metre, although it may let you drop a lining or interfacing.
Ask the mill for two or three weights of the same construction as hanger samples, wash them, and compare after laundering rather than off the roll. A tolerance of around plus or minus 5 per cent on GSM is common from Indian mills; tighter tolerances are possible but usually cost more and need a mill with good process control.
How Creston & Co helps
We help buyers settle the right GSM at the specification stage, then hold the mill to it. Sealed samples go to an NABL-accredited lab for finished weight, and we check rolls again before loading and supervise the container. We usually set up one approved supplier plus one backup so a weight problem at one mill does not stop your programme, and a free 20-minute sourcing review is the simplest way to begin.