What Is GSM in Fabric? A Guide for Custom Apparel
STX Garment Buyer Guide
GSM means grams per square meter: the mass of fabric over a defined area. It helps describe fabric weight, but it does not tell you everything about softness, warmth, durability or garment quality. For a custom clothing order, specify GSM together with fiber composition, fabric construction, finish and an approved physical sample.
What Fabric GSM Measures
GSM describes fabric, not the total weight of a finished garment. A hoodie can weigh more than a T-shirt because it uses more fabric and includes a hood, ribbing, pockets and trims. Two fabrics with the same GSM can feel different because their yarns, knitting structure, fiber blend and finishing are different.
The basic calculation is fabric mass in grams divided by fabric area in square meters. For example, a 100 cm² specimen has an area of 0.01 m². If it weighs 3.2 g, the calculated fabric weight is 320 g/m². This example explains the unit; it is not a certified laboratory test. Agree on the sampling conditions, test method and acceptance tolerance with the supplier.
Choose Weight Together With Construction
| Decision | What to specify | Why it matters |
|---|---|---|
| T-shirt body | Jersey construction, fiber blend, target GSM and opacity | Weight alone does not define drape, stretch or transparency. |
| Loopback sweatshirt | French terry structure, loop character and surface finish | The inner loops and finishing affect hand feel. |
| Brushed hoodie | Fleece construction, brushing and target GSM | The brushed surface changes feel; assess a sample for the intended season. |
| Rib and contrast panels | Separate material specification for each component | One body-fabric GSM does not cover every panel or trim. |
A heavier fabric is not automatically better. Start with the intended fit, climate, retail positioning and decoration. Ask for fabric options against those requirements, then compare physical swatches and a garment sample. Avoid selecting a fabric from a GSM number or reference photograph alone.
French Terry vs Fleece: Ask the Right Questions
French terry usually has loops on the reverse; brushed fleece has a raised inner surface. Compare the actual fabrics rather than assuming every terry or fleece behaves identically. Confirm the body composition, inside surface, stretch, recovery, shrinkage expectations and appearance after the agreed wash test. A structured oversized hoodie and a soft fitted sweatshirt may need different choices even at similar GSM.
Fabric Specification Checklist for a Quote
- Style reference, intended fit, season and end use.
- Fibre composition and fabric construction for body, rib and contrast panels.
- Target GSM and an agreed tolerance, with a physical swatch where available.
- Colour reference, finish, brushing or washing requirements.
- Printing or embroidery method, artwork size and placement.
- Required performance checks and approval criteria.
- Quantity per style and color, size breakdown and target timeline.
Separate confirmed requirements from open choices. If you do not know the exact GSM, describe the desired hand feel and silhouette and request options. Final material availability, price and minimums should be confirmed in the project quotation.
Compare Fabric Choices Against Product References
Start with our fabric sourcing and material selection capability and the Custom Hoodie Manufacturer hub. Then review the French terry puff print and flocking sweatshirt reference and washed cropped zip hoodie reference. These are design and construction references; they do not establish an exact GSM or identical specifications for your order.
Send the selected reference, material brief and quantity through Request a Manufacturing Quote. We can assess options against your specification before sampling.
Fabric GSM FAQs
Is a higher GSM always better?
No. The appropriate weight depends on the product, construction, desired feel and end use. Compare samples and the full specification.
Can I compare GSM across different fabrics?
You can compare mass per area, but the number alone does not compare all performance or feel characteristics.
Is GSM the same as garment weight?
No. Garment weight includes the amount of fabric used, trims and other components.
What if I do not have a GSM specification?
Share a physical reference or describe the intended feel, fit and season. Ask for material options and approve the selected fabric before bulk production.
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