Reference
Fabric GSM guide
GSM — grams per square metre — is the standard way fabric weight is specified, and the number most often argued about at inspection. This guide gives typical GSM by fabric type and by garment, the ounce equivalents, and the one ambiguity that causes most disputes.
To convert a specific figure, use the fabric weight converter. For roll weight and cost per metre, use the GLM calculator.
What GSM does and does not tell you
GSM measures weight per unit area, independent of width. That is its strength: two fabrics at 180 GSM weigh the same per square metre whether they are 44 inches or 60 inches wide.
But GSM says nothing about how a fabric feels. A 180 GSM fabric made from 40s combed cotton in a fine construction and a 180 GSM fabric made from 20s carded in an open construction are the same weight and completely different cloths. Weight is one parameter, not a specification.
GSM by fabric type
| Fabric | GSM | oz/yd² | Character |
|---|---|---|---|
| Voile | 70 – 90 | 2.1 – 2.7 | Sheer, open, very light |
| Lawn / mulmul | 90 – 110 | 2.7 – 3.2 | Fine, soft, semi-sheer |
| Poplin | 110 – 140 | 3.2 – 4.1 | Crisp, smooth, warp-faced |
| Cambric | 120 – 150 | 3.5 – 4.4 | Balanced plain weave |
| Twill / drill | 200 – 300 | 5.9 – 8.8 | Diagonal rib, durable |
| Canvas / duck | 400 – 550 | 12 – 16 | Heavy, stiff, structural |
| Single jersey | 140 – 200 | 4.1 – 5.9 | Light knit, T-shirt weight |
| Interlock | 200 – 260 | 5.9 – 7.7 | Double knit, stable, opaque |
| Rib | 220 – 300 | 6.5 – 8.8 | Stretchy, used for cuffs and body |
| Pique | 200 – 250 | 5.9 – 7.4 | Textured, polo shirt fabric |
| Fleece | 260 – 340 | 7.7 – 10 | Brushed back, sweatshirt weight |
| Denim (light) | 240 – 300 | 7 – 9 | Shirts, summer jeans |
| Denim (mid) | 300 – 400 | 9 – 12 | Standard jeans |
| Denim (heavy) | 400 – 480 | 12 – 14 | Rigid and selvedge jeans |
| Terry towel | 350 – 650 | 10 – 19 | Varies with pile height |
GSM by garment — what to specify
| Product | Recommended GSM | Notes |
|---|---|---|
| Basic T-shirt | 150 – 170 | Below 140 feels thin and can show through |
| Premium T-shirt | 180 – 220 | Better drape and opacity, higher perceived value |
| Polo shirt | 200 – 250 | Pique construction holds shape at the collar |
| Formal shirt | 110 – 140 | Poplin; heavier reads as casual |
| Sweatshirt / hoodie | 280 – 340 | Fleece; below 260 loses warmth and structure |
| Jeans | 340 – 400 | Mid weight suits most markets year-round |
| Bedsheet | 120 – 180 | Thread count matters more than GSM here |
| Bath towel | 450 – 600 | Higher GSM means more absorbency and slower drying |
| Curtains / drapery | 180 – 300 | Depends on lining and whether blackout is needed |
GSM and oz/yd² together
The conversion is fixed: 1 oz/yd² = 33.906 g/m². Divide GSM by 33.906 for ounces; multiply ounces by 33.906 for GSM.
Denim is the exception where imperial dominates worldwide. Indian mills quote 12 oz denim, not 407 GSM, and buyers expect it that way. For everything else in India, GSM is the working unit.
Greige, finished or after-wash — the ambiguity that causes disputes
A GSM figure means nothing without knowing which stage it refers to. Fabric gains weight if it is compacted or coated, and loses it in desizing, scouring and washing. Shifts of 5 to 12 per cent between greige and finished are entirely normal.
Most GSM arguments at inspection are not about the fabric. They are about two parties measuring at different stages and both being right.
Write it explicitly: “180 GSM ±5%, finished, after one wash”. That single line removes the argument before it starts.
Tolerances worth agreeing
GSM is never exact. A ±5 per cent tolerance is normal for woven fabric and ±5 to 7 per cent for knits, which relax more. Asking for ±2 per cent is possible but you will pay for it, and on knitted fabric it is close to unachievable in production.
Frequently asked questions
What GSM is a good T-shirt?
Most T-shirts sit between 150 and 180 GSM. Below 140 feels thin and can show through; 180 to 220 reads as premium.
How do I convert GSM to oz/yd²?
Divide GSM by 33.906. A 200 GSM fabric is 5.9 oz per square yard.
How many GSM is 12 oz denim?
12 oz per square yard is 407 GSM. Multiply the ounce figure by 33.906.
Is higher GSM always better?
No. Higher GSM means heavier, not better. The right weight depends on the garment, the season and the market.
Does GSM change after washing?
Yes, usually. Fabric relaxes and shrinks, so finished and after-wash GSM differ from greige. Always state which stage your figure refers to.
What GSM tolerance is realistic?
Around ±5 per cent for woven and ±5 to 7 per cent for knitted fabric. Tighter tolerances are possible but cost more.
Can you supply fabric to a target GSM?
Yes. Give us the construction, width, target GSM and whether it is greige or finished, and we will quote and hold it lot to lot.
Need this quoted?
Send your count, blend and quantity and we will come back with firm pricing ex-Delhi and a lead time, within one working day.
Get a quote