Fabric Weight Converter

Fabric weight describes how heavy a material is per unit area. Quilters and US retailers often list oz/yd² (ounces per square yard). International suppliers and technical specs use GSM (grams per square meter). Both measure the same property — area density.

Light quilting cotton is often 4–5 oz/yd² (135–170 GSM). Heavy canvas may exceed 12 oz/yd² (400+ GSM). Weight affects drape, warmth, and structure — compare like units when substituting fabrics in a pattern.

The conversion factor is fixed: 1 oz/yd² = 33.906 GSM. Multiply oz/yd² by 33.906 to get GSM, or divide GSM by 33.906 for oz/yd². This works for any woven or knit fabric where the label gives area weight.

Worked example with the default 5.5 oz/yd²: 5.5 × 33.906 ≈ 186 GSM. That sits in the mid-weight quilting cotton range — substantial enough for bags and structured garments, lighter than canvas or denim.

GSM alone does not tell thread count, fiber content, or finish. A 200 GSM linen feels different from 200 GSM fleece because structure and loft differ. Use weight as one data point alongside drape samples and pattern recommendations.

Quilters sometimes compare batting by oz/yd² as well — this converter applies to fabric and batting labels that use the same units. Double-check whether a supplier quotes per square yard or per linear yard (those are not the same).

When shopping online, suppliers may list only GSM while US quilt shops use oz/yd². Convert before comparing a Kona cotton bolt to a European linen swatch so you are not surprised by drape or bulk when the fabric arrives.

Limits: coated fabrics, leather, and foam-backed materials may list weight differently. This tool converts between oz/yd² and GSM only — not linear yard weight or thickness in mils.