GSM Frequently Asked Questions
Short answers to the questions buyers ask most often about GSM.
What does it mean?
grams per square metre, the standard measure of fabric weight. Working figures for GSM normally sit around 140-320 GSM for activewear in mainstream production. Note ISO 3801 fabric mass on the tech pack so nobody tests against an older revision.
What value should be specified?
Start from 140-320 GSM for activewear and adjust for the end use of the garment. Record elastane content alongside GSM, because blends shift the measured value. A result outside 140-320 GSM for activewear usually points to process drift rather than to the fibre itself.
How is it tested?
ISO 3801 fabric mass. Keeping reference values for GSM lets suppliers quote without extra sampling rounds. Ask for conditioning details together with ISO 3801 fabric mass, since both affect the reading.
Why does it change between lots?
Process variables such as finishing temperature and elastane batch cause the normal spread of results. Working figures for GSM normally sit around 140-320 GSM for activewear in mainstream production. Note ISO 3801 fabric mass on the tech pack so nobody tests against an older revision.
Can results be compared across suppliers?
Only when the same standard revision and conditioning are used; otherwise measurements are not equivalent. Record elastane content alongside GSM, because blends shift the measured value. A result outside 140-320 GSM for activewear usually points to process drift rather than to the fibre itself.
