Tool · Last checked 2 October 2026
oz to gsm calculator
Convert fabric weight between ounces per square yard (oz/yd²) and grams per square metre (gsm). It works both ways and runs in your browser.
Optional: ounces per linear yard
At this width the fabric weighs .
The formula
gsm = oz/yd² × 33.906 and oz/yd² = gsm ÷ 33.906
Where the factor comes from: one avoirdupois ounce is 28.349523 g and one yard is exactly 0.9144 m, so one square yard is 0.83612736 m². 28.349523 ÷ 0.83612736 = 33.9057 g/m², usually rounded to 33.906. NIST lists 1 oz/yd² as 3.390 575 × 10⁻² kg/m².[1]
Worked examples
- A 5 oz/yd² jersey: 5 × 33.906 = 169.5 gsm.
- A 220 gsm stretch knit: 220 ÷ 33.906 = 6.49 oz/yd².
- A 10 oz/yd² fleece: 10 × 33.906 = 339.1 gsm.
Square yard or linear yard?
Fabric weight in ounces is quoted two ways. Ounces per square yard is measured on a 36 × 36 inch piece. Ounces per linear yard is measured on a piece 36 inches long by the full width of the fabric.[2] This calculator converts square-yard figures. If you know a fabric's width, the optional field shows the linear-yard weight: oz per linear yard = oz/yd² × width (in) ÷ 36.
Quick reference
| oz/yd² | gsm |
|---|---|
| 3 | 101.7 |
| 4 | 135.6 |
| 5 | 169.5 |
| 5.5 | 186.5 |
| 6 | 203.4 |
| 6.5 | 220.4 |
| 7 | 237.3 |
| 8 | 271.2 |
| 9 | 305.2 |
| 10 | 339.1 |
| 11 | 373.0 |
| 12 | 406.9 |
| 13 | 440.8 |
| 14 | 474.7 |
| 16 | 542.5 |
For what these numbers mean in practice, see the Fabric Weight Index. It explains what gsm is, lists typical weight ranges by garment type, and gives the fabric weight of every Quiet Unity piece.
Sources
- 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/
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