Knitwear's Secret Weapons: Yarn Count and GSM
Yarn count measures fineness — 1 g of fibre spun into 100 m is 100S — so higher count means finer, softer yarn, but not automatically better: very high counts are delicate and pill more. GSM measures fabric weight per square metre: 100–200 for light knits, 200–350 for regular, 350+ for heavy. The best sweaters pair high count with medium-high GSM, such as 80S / 380 GSM.
Higher count is not always better, and heavier is not always warmer. A plain-language guide to yarn count and GSM — and how the two work together.
Shopping for knitwear online, you keep running into technical terms: “80-count two-ply pure cashmere”, “this cardigan weighs 400 grams”.
To most shoppers these numbers read like code. Is a higher count always better? Is a heavier knit always warmer? Here is what actually sits behind count and GSM.
1. Count: how fine is the yarn?
What is yarn count?
Count measures how fine a yarn is: from one unit weight of fibre, how many units of length can be spun. The higher the count, the finer the yarn.
Take one gram of wool: if it spins into 100 metres of fine yarn, it is 100-count (100S); if only 50 metres, it is 50-count (50S).
- In the hand: higher counts knit into a finer, smoother fabric with a silk-like sheen; lower counts feel coarser, thicker and more grainy.
Is a higher count always better?
This is the biggest misconception. “120-count must be better than 60-count” is not true — it depends on what the garment is for.
- For next-to-skin luxury — cashmere sweaters, merino base layers — high counts (80S–120S) deliver unmatched softness and lightness.
- For durability and structure — chunky cable knits, coat-style cardigans — lower counts (26S–48S) keep the garment substantial and hard-wearing. Very high counts are delicate and pill more easily.
2. GSM: how heavy is the fabric?
GSM stands for grams per square metre — the weight of one square metre of knitted fabric. The higher the GSM, the heavier and thicker the fabric.
It is the quickest way to tell whether a piece is light and breathable or heavy and cold-weather ready.
Common GSM ranges
- Light (100–200 GSM): transitional knit tees and thin base layers — barely-there weight, excellent breathability.
- Medium (200–350 GSM): the most common spring/autumn crewnecks and cardigans, balancing warmth and drape.
- Heavy (350 GSM+): deep-winter wool and cashmere sweaters, heavyweight turtlenecks and knit coats — maximum wind resistance and warmth.
3. The golden pairing: how count and GSM work together
Looking at either number alone is misleading. The best knits balance the two.
- High count + medium-high GSM (e.g. 80S / 380 GSM): the ideal pairing — fine, soft and lustrous, yet substantial enough to keep you warm. Usually the most expensive.
- High count + low GSM (e.g. 100S / 150 GSM): extremely light and elegant — spring/summer or air-conditioned-office layering.
- Low count + high GSM (e.g. 24S / 500 GSM): a chunky, retro handle — heavy, wind-resistant, perfect for oversized boyfriend fits or vintage collegiate looks.
Next time you buy a sweater, check the label like an insider
Before you commit, ask one simple question: “What are the count and GSM of this piece?”
- For a soft, refined, next-to-skin feel: choose a higher count (48S+) with a moderate GSM.
- For maximum warmth and durability: look for a higher GSM and a tightly knitted structure.
- With these two numbers in hand, vague marketing words like “premium” and “heavyweight” stop working on you.
Is a higher yarn count always better?
No. Very high counts are finer and softer but also more delicate and pill more easily, so count has to match the garment's use.
What counts as a heavyweight sweater?
Around 500 g and above per piece; 3G–5G chunky styles commonly run 500–900 g.
What does 80S / 380 GSM mean?
A high-count yarn knitted at medium-high weight — fine, soft and still warm. It is a premium combination.
How do I judge quality quickly?
Check four numbers: fibre composition, yarn count, garment weight and gauge.
Olivia handles operations content for Jinya, covering knitwear sourcing, product development and garment care — turning the questions buyers ask on the factory floor into practical, checkable guides.
Ms. Liu has run knitting floors for more than 20 years, overseeing yarn routing, machine programming, linking and final QC. She reviews every technical claim published here.
