Yarn count converter
Convert a yarn count between all five common systems at once, work out the resultant count of a folded yarn, and estimate woven GSM from EPI, PPI and yarn counts.
Convert a count
Indirect system - a higher number means a finer yarn.
Leave at 1 for a singles yarn.
| System | Value | Type |
|---|---|---|
| Ne | 30 | indirect |
| Nm | 50.8 | indirect |
| tex | 19.68 | direct |
| dtex | 196.83 | direct |
| denier | 177.15 | direct |
Resultant count (2/30 Ne)
15Ne
39.37 tex. Linear densities add in tex, which is why a 2/40s Ne folded yarn behaves as 20s Ne, not 80s.
Woven fabric GSM from construction
GSM ≈ (EPI ÷ warp Ne + PPI ÷ weft Ne) × 25.6
Indicative GSM
153.6g/m²
This formula ignores crimp and finish, so treat it as a planning figure. For a spec sheet, cut a swatch with a GSM cutter and weigh it.
How this is calculated
Every conversion here routes through tex as a pivot, so there is one constant per system instead of a matrix of pairwise formulas - and no chance of two routes disagreeing.
Indirect systems measure length per unit mass, so higher is finer: tex = 590.5 ÷ Ne and tex = 1000 ÷ Nm.
Direct systems measure mass per unit length, so higher is coarser: tex = dtex ÷ 10 and tex = denier ÷ 9.
Folded yarn. Plying adds linear density, so the resultant tex is the singles tex multiplied by the number of plies. In an indirect system that means the count number falls - 2/40s Ne is a 20s Ne yarn. Both forms are shown so the notation cannot mislead you.
Woven GSM. GSM ≈ (EPI ÷ warp Ne + PPI ÷ weft Ne) × 25.6, the shop-floor approximation for grey woven fabric.
Questions
- Does a higher count mean a finer yarn?
- It depends on the system. In indirect systems - Ne and Nm - a higher number means a finer yarn, because the number is length per unit mass. In direct systems - tex, dtex and denier - a higher number means a coarser yarn, because the number is mass per unit length. Mixing the two up is the most common yarn-count error.
- How do I convert Ne to tex?
- tex = 590.5 ÷ Ne, and Ne = 590.5 ÷ tex. The constant comes from the definition of the English cotton count: one hank is 840 yards and one pound is 453.6 grams, so 453.6 × 1000 ÷ 768.1 ≈ 590.5.
- What is the difference between tex, dtex and denier?
- They are the same kind of measurement at different lengths: tex is grams per 1,000 metres, dtex is grams per 10,000 metres, and denier is grams per 9,000 metres. So dtex = tex × 10 and denier = tex × 9.
- Why does 2/40s Ne behave like 20s, not 80s?
- Because linear densities add. Two 40s Ne singles twisted together carry twice the mass per unit length, so the resultant is 20s Ne - coarser, not finer. Converting to tex makes this obvious: 40s Ne is about 14.8 tex, and two of them make 29.5 tex, which is 20s Ne.
- How accurate is the GSM estimate?
- It is a planning figure. The formula ignores crimp, finish, shrinkage and any coating, so a finished fabric usually weighs more than it predicts. For a spec sheet, cut a swatch with a GSM cutter and weigh it.
Sources & verification
The conversion constants are definitional: they follow from how each numbering system is specified, not from any empirical measurement. 590.5 for Ne, 1000 for Nm, 9 for denier and 10 for dtex are exact within the rounding of the English count constant.
The GSM formula is an approximation used for planning and quotation. It is not a substitute for a weighed swatch, and it does not apply to knits.