Fabric Weight (GSM) Calculator
Convert fabric weight between grams per square meter (GSM) and ounces per square yard. You can also find how much a piece of fabric weighs from its width and length.
What fabric weight is
Fabric weight (GSM, grams per square meter) is the mass of one square meter of fabric, in g/m². An explanatory reference (Wikipedia, "Units of textile measurement") presents g/m² (sometimes abbreviated GSM) as the metric measure of how heavy a fabric is. It relates to the thickness and the strength of the fabric.
In the United States and some other places, fabric weight is also given in oz/yd² (ounces per square yard). For example, the explanatory reference on canvas (Wikipedia, "Canvas") says that canvas is classified by the ounces per square yard.
The definitions used
- 1 oz (international avoirdupois ounce) = 28.349523125 g (one sixteenth of 1 lb = 0.45359237 kg, from the 1959 international yard and pound agreement)
- 1 yd (international yard) = 0.9144 m, so 1 yd² = 0.83612736 m²
- 1 oz/yd² = 28.349523125 g ÷ 0.83612736 m² = about 33.9057 g/m² (calculated from the definitions)
This is not the troy ounce (about 31.1035 g) used for precious metals; it is not used for fabric. The calculation uses exact fractions, and values that do not divide evenly are marked as rounded values.
How the weight is found
Weight = fabric weight × area (width × length). The width and the length can each be entered in their own unit. The weight is shown in g, kg, oz and lb.
Examples
| Calculation | Input | Result |
|---|---|---|
| Converting fabric weight | 200 g/m² | about 5.899 oz/yd² |
| Converting fabric weight | 10 oz/yd² | about 339.06 g/m² |
| Weight | 200 g/m², width 150 cm, length 2 m | area 3 m², weight 600 g |
Things to know
- The fabric weight is the value printed for the product, and it differs from a measured value because of moisture, test conditions, stretch and how the edges are handled. The weight found here is a theoretical value (fabric weight × area), and the real weight is different.
- Check in the product description whether an oz figure means ounces per square yard. For canvas, the ounces-per-square-yard convention was confirmed in the reference, but how other fabrics use oz was not.
- Typical fabric weights for each kind of fabric, judgments such as "heavy" or "light", yarn thickness, weight per linear yard, and shrinkage or waste are not covered.
- To convert weights, use the Weight Converter. To convert areas, use the Area Converter. To convert lengths, use the Length Converter.
Sources and checks
The definitions were checked against explanatory references (Wikipedia: "Ounce", "Yard", "Pound (mass)", "Units of textile measurement" and "Canvas") when the Japanese version was made (October 30, 2026). They were not checked again for the English version, and none of them is a standard.
Frequently asked questions
How many oz/yd² is 200 g/m²?
About 5.899 oz/yd² (200 ÷ 33.9057).
How many g/m² is 10 oz/yd²?
About 339.06 g/m² (10 × 33.9057).
Can I use the troy ounce?
No. The troy ounce is a different unit, used for precious metals. For oz/yd² of fabric, the calculation uses the international avoirdupois ounce.