Every manufacturer will throw fabric specs at you before you've had a chance to ask a single question. GSM, ring-spun, combed, open-end, slub, French terry — it sounds like jargon designed to confuse you. It isn't. Each term describes one specific thing about how the fabric was made, and once you understand the handful that actually matter, you can make smarter sourcing decisions and write better tech packs.
GSM: The Number That Tells You the Most
GSM stands for grams per square metre — it's the weight of the fabric. Higher GSM means heavier, denser fabric. Lower GSM means lighter and more breathable. For t-shirts, the number is almost the first thing you should look at because it determines hand-feel, drape, print surface, and price point perception more than any other single spec.
Weight | GSM | Best for |
|---|---|---|
Lightweight | 140 GSM | Summer basics, resort wear, layering pieces |
Mid-weight | 180 GSM | Everyday tees, most streetwear basics |
Heavy | 220 GSM | Premium streetwear, structured silhouettes |
Heavyweight | 280 GSM | Luxury basics, boxy fits, high-end positioning |
The GSM of a blank is set during knitting and cannot be changed — confirm it from the fabric mill certificate, not just the factory's quote.
A mid-weight 180 GSM tee is the industry standard for a reason: it's substantial enough to feel premium but light enough to wear comfortably. If your brand is positioning above the $40 retail price point, you should seriously consider 220+ GSM. Below it, the garment will feel thin on the hanger — which affects perception at the point of sale even before the customer tries it on.
Ring-Spun vs. Open-End Spun
These terms describe how the yarn was made from raw cotton fibres — and the difference shows up directly in how the finished t-shirt feels.
Ring-spun yarn is made by twisting and thinning cotton fibres until they form a tightly wound strand. The result is a stronger, smoother, softer yarn. It costs more to produce and is slower to make, which is why ring-spun fabrics cost more per metre. For most branded clothing, ring-spun is the baseline standard.
Open-end spun yarn (also called rotor-spun) is produced faster and cheaper by feeding fibres directly into a rotor. The resulting yarn is coarser and more uneven. It's used in budget blanks, promotional tees, and workwear — not in branded fashion.
If a factory doesn't specify ring-spun in their quote, assume it's open-end. Always ask explicitly: "Is this ring-spun?" and get confirmation in writing before sampling.
Combed vs. Uncombed Cotton
Combing is an extra step after spinning where the yarn is passed through fine metal teeth to remove short fibres and align the longer ones. Combed cotton is noticeably smoother, less prone to pilling, and takes dye more evenly — meaning your colour will be more consistent across a production run.
The gold standard is combed ring-spun cotton. This is what you'll find in the blanks used by most premium streetwear brands. It costs more than uncombed, but the difference in hand-feel is obvious the moment you hold both up.
"Combed ring-spun cotton is to a t-shirt what good leather is to a shoe. You can make it cheaper, but the hand tells you everything."
What to Order Based on Your Positioning
Price Point | Fabric Spec | Typical Retail |
|---|---|---|
Budget / promo | Open-end, 150–160 GSM, 100% cotton | $15–$25 |
Mid-market | Ring-spun, 180 GSM, 100% cotton most streetwear brands start here | $35–$55 |
Premium | Combed ring-spun, 220 GSM, 100% cotton or cotton/modal blend | $55–$90 |
Luxury | Combed ring-spun, 280+ GSM, Supima or Pima cotton | $90+ |
Your fabric spec and your retail price need to match. A 280 GSM Pima cotton tee priced at $35 kills your margin. A 150 GSM open-end tee at $70 kills your credibility. Pick a tier and own it consistently across your range — consumers notice inconsistency in quality faster than they notice it in design.
Three Questions to Ask Every Fabric Supplier
"Can you provide the mill certificate for this fabric?" — This is the only way to verify GSM, composition, and wash-fastness independently of what the factory tells you.
"What is the shrinkage after the first wash?" — Industry standard is under 5%. Request a pre-washed sample alongside the dry sample before confirming your sizing.
"Is this fabric certified?" — OEKO-TEX Standard 100 confirms no harmful chemicals were used. GOTS certifies organic claims. If you're marketing as sustainable, you need the certification, not just the factory's word.