GSM means grams per square meter. It measures mass per unit of fabric area. Ounces per square yard measure the same property in different units. Ounces per linear yard measure the weight of a yard-long piece at a particular fabric width, so they cannot be compared directly without knowing that width.
Convert ounces per square yard to GSM
Multiply oz/yd² by approximately 33.906 to get GSM. Divide GSM by 33.906 to get oz/yd². These calculations convert units; they do not establish a fabric's drape, opacity, stretch, or suitability.
| Ounces per square yard | Approximate GSM |
|---|---|
| 5 oz/yd² | 170 GSM |
| 6 oz/yd² | 203 GSM |
| 7.5 oz/yd² | 254 GSM |
| 8.5 oz/yd² | 288 GSM |
| 9.5 oz/yd² | 322 GSM |
| 12 oz/yd² | 407 GSM |
| 14 oz/yd² | 475 GSM |
What if the weight is per linear yard?
A linear yard is 36 inches long at the full fabric width. A yard of 60-inch-wide fabric covers 60 ÷ 36, or about 1.667 square yards. To convert ounces per linear yard to ounces per square yard, divide by the width in yards.
Example: 20 ounces per linear yard at 60 inches wide is 20 ÷ 1.667 = 12 oz/yd², or approximately 407 GSM. The same 20-ounce linear weight at another width gives a different GSM.
If a listing says only “oz,” confirm whether it means per square yard or per linear yard before comparing it with another fabric. Fabric weight is also different from the packed shipping weight of your order.
Use actual specifications to narrow your choice
The enzyme-washed Tencel gabardine lists a standard weight of 7.5 oz per square yard, with Sky Blue at 6 oz and Purple at 8.5 oz. Those convert to approximately 254, 203, and 288 GSM respectively.
The ivory PFD Tencel gabardine lists 9.5 oz per square yard, or approximately 322 GSM. That number is useful for comparing mass, but a swatch is still the best way to judge its hand for your particular pattern.
Match weight to your sewing pattern
- T-shirts and knit dresses: compare jersey knits using the pattern's fabric and stretch requirements.
- Hoodies and joggers: compare French terry with fleece, including the back finish and recovery.
- Jeans and jackets: check denim weight, stretch, shrinkage information, and your machine's ability to handle bulky seams.
Does higher GSM mean better quality?
No. A higher number means greater mass over the same area. A lightweight fabric can be the right choice for one project and unsuitable for another. Fabric construction, yarn, finishing, color, and intended use also matter; weight alone does not guarantee warmth, durability, or opacity.
Does heavier fabric require more yardage?
Yardage is a length requirement. Your pattern, size, fabric width, layout, pattern matching, and shrinkage allowance determine how much length you need. Use our yardage guide as a planning aid, then follow your specific pattern.