Fabric GSM Converter
Fabric weight is expressed in grams per square meter (GSM, g/m²) or ounces per square yard (oz/yd²). These are not simple ratios — one ounce per square yard equals approximately 33.9 grams per square meter.
Formula
oz/yd² = g/m² × 0.02949352468 g/m² = oz/yd² × 33.90574744
Formula variables
- g/m² (GSM) — grams per square meter.
- oz/yd² — ounces per square yard.
- 0.02949352468 — the conversion factor. Derived from 1 oz = 28.349523125 g and 1 yd² = 0.83612736 m².
Worked Examples
Example 1: 150 GSM to oz/yd²
- Multiply: 150 × 0.02949352468 = 4.424.
- Result: 150 g/m² ≈ 4.42 oz/yd².
Example 2: 200 GSM to oz/yd²
- Multiply: 200 × 0.02949352468 = 5.899.
- Result: 200 g/m² ≈ 5.90 oz/yd². Typical medium-weight denim.
Example 3: 10 oz/yd² to GSM
- Multiply: 10 × 33.90574744 = 339.06.
- Result: 10 oz/yd² ≈ 339 g/m². Heavy denim / canvas.
Example 4: 5 oz/yd² to GSM
- Multiply: 5 × 33.90574744 = 169.53.
- Result: 5 oz/yd² ≈ 170 g/m². Medium t-shirt weight.
Common Fabric Weights
| Fabric | g/m² (GSM) | oz/yd² |
|---|---|---|
| Chiffon | 30–60 | 0.9–1.8 |
| Light cotton voile | 70–90 | 2.1–2.7 |
| Standard t-shirt jersey | 140–160 | 4.1–4.7 |
| Heavyweight t-shirt | 180–220 | 5.3–6.5 |
| Light denim | 200–250 | 5.9–7.4 |
| Medium denim | 280–340 | 8.3–10.0 |
| Heavy denim (raw) | 400–500 | 11.8–14.7 |
| Canvas (light) | 250–300 | 7.4–8.8 |
| Canvas (heavy) | 400–500 | 11.8–14.7 |
| Wool coating | 300–500 | 8.8–14.7 |
| Terry cloth towel | 400–600 | 11.8–17.7 |
| Leather (typically) | 600–1500 | 17.7–44.2 |
Real-World Uses
- Textile manufacturing: Fabric weight determines durability, drape, warmth, and cost. It is a key quality metric.
- Apparel design: Designers specify fabric weight in GSM or oz/yd² depending on the manufacturer's location.
- Denim and canvas: Historically, denim is measured in oz/yd² (e.g., "14 oz denim"). Modern specifications may use GSM.
- T-shirt production: T-shirt weight is often quoted in oz/yd² (US) or GSM (international).
- Upholstery and home textiles: Heavier fabrics (250+ GSM) are used for durability in furniture.
- Print-on-demand: Print services often specify fabric weight to help customers choose between light, medium, and heavy garments.
Unit Definitions
Grams per square meter (GSM, g/m²)
A metric unit of fabric weight equal to the mass of one square meter of fabric in grams. Used internationally for textiles, paper, and other sheet materials.
Ounces per square yard (oz/yd²)
A customary unit of fabric weight equal to the mass of one square yard of fabric in ounces (avoirdupois). Common in the US textile industry.
Related Converters
Frequently Asked Questions
How many oz/yd² in 1 GSM?
One gram per square meter equals approximately 0.0295 ounces per square yard. Conversely, 1 oz/yd² ≈ 33.91 g/m².
What does 5.3 oz mean for a t-shirt?
"5.3 oz" typically means 5.3 oz/yd², which is about 180 g/m². This is a medium-weight t-shirt fabric.
What is a good GSM for a t-shirt?
Standard t-shirts are 140–160 GSM (4.1–4.7 oz). Premium/heavyweight t-shirts are 180–220 GSM (5.3–6.5 oz). Lightweight or summer shirts are 110–140 GSM.
What GSM is 14 oz denim?
14 oz/yd² denim is approximately 475 g/m². This is heavy raw denim, typically used for high-quality jeans that will fade distinctly over time.
Is heavier GSM always better?
Not necessarily. Heavier fabric is more durable and warmer, but less breathable. For summer clothing, light fabric (120–150 GSM) is more comfortable. For upholstery, 300+ GSM is better for durability.