Guide · Last checked 2 October 2026
The Fabric Weight Index
What gsm means, the weight ranges used for different garments, and the fabric weight of every piece we make.
What is gsm?
gsm stands for grams per square metre (g/m²): the mass of one square metre of fabric. It is the metric way to state fabric weight. In the United States the same property is usually given in ounces per square yard (oz/yd²).[4]
Fabric weight is measured by weighing a conditioned sample of known size and scaling the result to a square metre. Standard test methods include ISO 3801 (woven fabrics) and ASTM D3776.[1][2]
Quick conversion: 1 oz/yd² = 33.906 g/m². Multiply ounces by 33.906 to get gsm, or divide gsm by 33.906 to get ounces.[3] Or use the oz to gsm calculator.
What fabric weight does and doesn't tell you
- How much fabric there is per square metre. A higher figure means a thicker, heavier construction,[6] and weight affects how a garment hangs and drapes.[4]
- Not quality on its own. Fibre content, yarn size and how densely the fabric is knitted or woven all set the weight.[4] A university lab study of cotton T-shirts quotes the view that there isn't necessarily a correlation between the thickness of a T-shirt's fabric and its quality.[5]
- Check the unit. “Ounces” can mean ounces per square yard or ounces per linear yard of a given width. They aren't the same, so compare like with like.[4]
- It shifts a little with washing. In the same study, the T-shirt fabrics measured heavier after repeated washing and drying, because of shrinkage.[5]
Typical fabric weights by garment type
General textile-industry categories, not a rule for any one product. The gsm figures are the source's oz/yd² ranges converted at 33.906 and rounded.
| Typical garments | Category | oz/yd² | gsm (approx.) |
|---|---|---|---|
| Sheer blouses, lingerie, tissue-weight knitted tops, T-shirts | Extra-light top weight | 1–3 | 34–102 |
| T-shirts, knitted tops, casual shirts, dresses, undergarments | Light top weight | 4–6 | 136–203 |
| Summer suits, dresses, jackets, knitted tops, trousers | Tropical weight | 4.5–8.5 | 153–288 |
| Pants, shorts, skirts, jeans, jackets, sweatshirts, all-season suits | Bottom / medium weight | 7–9 | 237–305 |
| Sweatshirts, sweatpants, denim, coats, parkas, cold-weather suits | Heavy bottom weight | 10–12 | 339–407 |
| Denim, jackets, winter coats, parkas, sweatshirts, sweatpants | Extra-heavy bottom weight | 14–16 | 475–542 |
Source: Textile Learner.[4] The same source calls fabrics of 6 oz/yd² (about 203 gsm) or less “top weight” and 8 oz/yd² (about 271 gsm) or more “bottom weight”.
A real-world check on T-shirts: a University of Kentucky lab study tested men's 100% cotton jersey T-shirts from three retail categories (mass merchant, fast fashion and “better”). Every fabric sample fell within the light top-weight range of 4–6 oz/yd². After five washes the lightest measured 4.89 oz/yd² (about 166 gsm) and the heaviest 5.63 oz/yd² (about 191 gsm).[5] Wikipedia gives typical cheap T-shirt fabric as about 150 gsm.[6]
Quiet Unity fabric weights
Every Quiet Unity product page lists the fabric weight in its Materials details, in gsm and ounces. Across the current range of 33 products, weights run from 110 to 420 gsm, with a median of 220 gsm. For 10 pieces the garment spec gives the weight in ounces; their gsm is converted at 33.906, rounded, and marked ~.
Read from each product's Materials details. The range changes as pieces come and go; the product page is always the current reference.
Sources
- ISO 3801:1977, Textiles: Woven fabrics: Determination of mass per unit length and mass per unit area (ISO). www.iso.org/standard/9335.html
- ASTM D3776/D3776M, Standard Test Methods for Mass Per Unit Area (Weight) of Fabric (ASTM International). store.astm.org/d3776_d3776m-20r25.html
- NIST Guide to the SI (SP 811), Appendix B.9: factors for units listed by kind of quantity. www.nist.gov/pml/special-publication-811/nist-guide-si-appendix-b-conversion-factors/nist-guide-si-appendix-b9
- Textile Learner, Fabric Specifications: Weight, Width & Performance Guide. textilelearner.net/fabric-specifications-weight-width-performance-guide/
- Easter, E. & Badgett, J. (2019). An Evaluation of the Quality of Men's 100% Cotton Jersey Knit T-Shirts. Journal of Textile Science & Fashion Technology 3(2). irispublishers.com/jtsft/fulltext/an-evaluation-of-the-quality-of-mens-100-cotton-jersey-knit-t-shirts.ID.000557.php
- Wikipedia, Units of textile measurement: Grams per square metre. en.wikipedia.org/wiki/Units_of_textile_measurement
Free to link to or cite with attribution. Related: oz to gsm calculator · Size guide