160 GSM, 220 GSM, 380 GSM — what do those numbers actually mean for your customer? A no-nonsense breakdown of fabric weights and their best use cases.
GSM (grams per square meter) is the single most-cited spec on a fabric swatch and the most misunderstood. It tells you the weight of one square meter of fabric — that is all. Drape, softness, and density depend on the knit structure too.
For tees: 140–160 GSM feels light and summery, 180–200 GSM is the modern standard, and 220–240 GSM enters "heavyweight" territory and starts to behave more like a structured garment. Above 240 GSM you are paying for fabric your customer may not need.
Hoodies live in a different range entirely. 280 GSM is on the lighter end, 320–380 GSM is the comfortable sweet spot for most premium streetwear brands, and 400–450 GSM enters "prison-yard" heavyweight — beautiful, but slow to dry and warm.
Joggers and sweatpants pair best with the same fleece weights as your hoodies. Matching your hoodie GSM means the set sells better as a tracksuit and ages at the same rate after washes.
Polyester behaves differently from cotton at the same GSM. Always touch a physical fabric swatch before locking in. Photos lie.
Understanding Fabric Construction, Weight, and Performance
Every fabric is a combination of fiber content, yarn count, knit or woven structure, and finish. Changing any one of these variables changes how the finished garment drapes, breathes, shrinks, pills, and photographs. Cotton jersey at 180 GSM knitted on a circular machine behaves completely differently from a 180 GSM interlock — same weight, same fiber, radically different hand feel, body, and durability under repeated laundering.
When reviewing a fabric for your collection, always ask for the full specification: fiber content, GSM, yarn count (Ne), knit structure, shrinkage rate after washing, and colorfastness rating. The first three define the garment's weight and feel; the last three define how it performs over the lifetime a customer wears it. A brand that ships 200 GSM tees that pill after four washes loses repeat customers — a far greater cost than investing in a better yarn specification upfront.
Fabric Sourcing, Swatches, and Color Approval
Fabric sourcing begins with the swatch room. Before any production order is placed, your factory will send physical swatches — typically 10×15 cm samples of candidate fabrics — for you to approve. This step is non-negotiable. Photos and screen renders lie; a fabric that looks warm honey-gold on your monitor may arrive as mustard yellow under warehouse lighting. Approval always happens under D65 standard lighting to simulate consistent natural daylight conditions.
Pantone references control color approval in apparel. Your tech pack specifies a Pantone code (e.g. Pantone 16-1350 TPX for dusty peach), the dyehouse dyes to that target, and the factory submits a lab dip — a fabric swatch dyed to match — for your sign-off. You compare the lab dip against the Pantone swatch under standard lighting and note whether it is on-target, too warm, too cool, or off in saturation. This cycle repeats until you approve, and only then does bulk dyeing begin.
Expert Tip Order one extra meter of your approved fabric alongside your bulk production. It becomes your "golden swatch" — the reference standard against which every QC inspection is measured. Factories that keep a golden swatch catch color drift in mid-production before it becomes a costly rejection at final inspection.
Frequently Asked Questions
How do I choose between cotton and polyester for performance wear?
Cotton breathes and feels natural but holds sweat and dries slowly. Polyester wicks moisture and dries fast but retains odor longer. Most performance brands use an 88/12 poly-spandex blend for stretch and recovery, or a 50/50 cotton-poly for lifestyle athleisure that leans more casual than athletic.
What is the minimum fabric quantity I can order?
Fabric mills typically require 300–500 meters per color. Your factory absorbs this if your order is large enough. For small runs, factories work from existing stock fabric — a narrower color palette but no minimums, and a two-week shorter production timeline.
What does "4-way stretch" mean and do I need it?
Four-way stretch means the fabric extends in both horizontal and vertical directions — essential for active wear, yoga pants, and any garment that must move with the body. Two-way stretch (horizontal only) is sufficient for t-shirts and sweatpants. For meaningful stretch recovery, specify at least 5% spandex/elastane in the blend.
Key Takeaways
- Always request and physically touch fabric swatches before approving — screen color renditions are unreliable.
- GSM alone does not define quality: yarn count, knit structure, and colorfastness rating matter equally.
- Color approval via lab dips under D65 standard lighting is mandatory before bulk dyeing begins.
- Keep a "golden swatch" from your approved fabric run as the QC benchmark throughout production.
- Performance wear works best in 88/12 poly-spandex; cotton-poly blends serve lifestyle-adjacent pieces.
MM
Written by
Md Mostain Salah Uddin
Member of the Essential Apparel production team, sharing first-hand insight from our Dhaka factory floor.
