Fabric formula
Fabric weight per unit area in grams per square meter, calculated from the weight and area of a cut sample.
GSM = W / A × 10,000
| Symbol | Meaning | Unit |
|---|---|---|
| W | Sample weight | g |
| A | Sample area | cm² |
Use it for every fabric weight check, from incoming fabric inspection to finished fabric approval. With a standard 100 cm² round cutter, the formula becomes GSM = W × 100.
A laboratory cuts a 20 cm × 20 cm specimen of a finished interlock and weighs it at 9.60 g.
With a 100 cm² round cutter the same fabric would give a sample of 2.40 g, and 2.40 × 100 = 240 g/m².
GSM is the weight of one square meter of fabric in grams. Learn how to measure it with a round cutter, calculate it from any sample size, estimate it from construction, and control it in production.
A practical reference of typical GSM ranges for knitted and woven apparel fabrics, what moves a fabric up or down the range, and how to use the chart when reviewing a specification.