Decitex describes the yarn. Cloth weight is GSM. Both belong on the spec line.
Decitex (dtex)
Decitex (dtex) is a unit of yarn linear density: the mass in grams of 10,000 meters of yarn. One dtex is one gram at that length, and lower dtex is finer yarn. It is the unit most European and international filament specs are written in.
Decitex (dtex) is grams per 10,000 meters of yarn: the mass of 10,000 meters of the strand, in grams. One dtex is one gram at that length, and a lower number is finer yarn. The name is deci-tex — one tenth of a tex — so 1 tex = 10 dtex. It is the unit most European and international filament specs are written in; North American buying writes denier, which takes 9,000 meters as its reference length instead.
dtex = mass (g) ÷ length (m) × 10,000
A yarn number, not a cloth weight
Decitex describes the filament, not the woven cloth. Cloth weight is GSM, grams per square meter, and the two move independently: a fine yarn in a dense sett can produce a heavier cloth than a coarser yarn in an open sett. A spec that carries a dtex count and no GSM has described half a fabric.
Decitex, tex and denier
The three units are one measurement — mass per length — read against a different reference length:
| Unit | Grams per | Where it is used |
|---|---|---|
| tex | 1,000 m | Coarse and technical yarns, engineering textiles |
| dtex | 10,000 m | Standard filament fineness, the continental and international convention |
| denier | 9,000 m | The North American convention, and the unit on most apparel and home-textile labels |
1 tex = 10 dtex, 1 dtex = 0.9 denier, and 1 denier ≈ 1.11 dtex.
Because the reference lengths differ, a bare number names no yarn: 150 dtex is 135 D, and 150 D is 167 dtex. The gap is small enough to pass a sample and fail a bulk order, which is why the unit belongs on the spec line beside the number.
Common polyester counts in both units
| Denier (D) | dtex | Typical use |
|---|---|---|
| 75 D | 83 dtex | Fine bed linen, microfiber-hand fabrics |
| 100 D | 111 dtex | Fine sheers, soft bedding |
| 150 D | 167 dtex | Standard polyester home-textile warp and weft |
| 200 D | 222 dtex | Mid-weight drapery |
| 210 D | 233 dtex | Common in continental specs |
| 300 D | 333 dtex | Curtains, heavier bedding |
| 400 D | 444 dtex | Upholstery base cloth |
| 600 D | 667 dtex | Technical and heavy furnishing |
| 1000 D | 1111 dtex | Coarse industrial and reinforcing yarn |
Each row is the same yarn on two scales, so a supplier quoting 111 dtex and a buyer asking for 100 D are describing one strand.
Why it appears on a European spec
Dtex is the continental and international convention for filament yarn fineness; denier remains the default in North American apparel and home-textile buying. Export specs frequently carry both — 150 D / 167 dtex — so a European mill quote and a US buyer's request can be matched without re-sampling.
Where it sits on a spec line
Three fields, three different questions:
| Field | Question it answers | Unit |
|---|---|---|
| Yarn dtex / denier | How fine is the strand? | dtex or D |
| GSM | How heavy is one square meter of cloth? | g/m² |
| Width | How wide is the finished roll? | cm |
Yarn fineness and cloth weight are independent, which is why a spec reading “150D fabric” is under-specified — and why “20D fabric” is still a yarn number, not a cloth weight.
How dtex and denier relate
The relation is fixed arithmetic, not a judgement call: D = dtex × 0.9, and dtex = D ÷ 0.9. The denier and dtex converter applies it in either direction. For the sister unit see denier; for the other half of the specification see GSM, and for how yarn choice moves the finished cloth see the polyester yarn denier guide.
Common questions
What is dtex?
- Dtex is decitex: the mass in grams of 10,000 meters of yarn. One dtex is one gram at that length, and a lower number is finer yarn. It is a yarn linear-density unit, not a fabric weight.
What does decitex mean?
- The name is deci-tex: one tenth of a tex, where tex is grams per 1,000 meters. So 1 tex is 10 dtex, and 1 dtex is one gram per 10,000 meters of the strand.
How does dtex compare with denier?
- Both measure mass per length. Dtex uses 10,000 meters and denier uses 9,000, so 1 dtex is 0.9 denier. 150 dtex is 135 D and 150 D is 167 dtex — the same yarn under two conventions.
Why do European specs quote dtex?
- Dtex is the continental and international convention for filament yarn fineness, while denier dominates North American apparel and home-textile buying. Export specs often carry both, so neither side has to re-sample to compare.
Is dtex a fabric weight?
- No. Dtex is yarn fineness; fabric weight is GSM, grams per square meter. A spec that names a dtex count but no GSM has not fixed the cloth.
Which dtex counts appear in polyester home textiles?
- Most polyester home-textile programs sit between 75 D and 150 D — 83 dtex to 167 dtex — for warp and weft, with heavier counts for curtains and upholstery. Sett, weave and finish still decide the GSM, so all three belong on the spec.
Related Terms
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