Denier to Tex Converter
Convert denier to tex, decitex, yarn count and mass per length for fibres, threads, hosiery, technical textiles and filament yarns. The tool also runs the reverse conversion so you can check specification sheets in either unit.
Yarn Linear Density Input
Converted Yarn Count
210 denier equals 23.33 tex because 1 tex equals 9 denier.
What Denier and Tex Measure
Denier
Denier is the mass in grams of 9,000 metres of fibre or yarn. A 210 denier yarn weighs 210 g per 9,000 m. It is common in hosiery, outdoor fabrics, thread labels and synthetic filament specifications.
Tex
Tex is the mass in grams of 1,000 metres. Because it uses 1,000 m, it works neatly with SI-style textile calculations. One tex equals 9 denier.
Decitex
Decitex, written dtex, is grams per 10,000 m. It is common in fibre and filament data sheets. One denier equals 1.111… dtex.
How to Use the Converter
Choose the input mode first. If a fabric label says 40D, 210D or 1000D, keep the mode on denier to tex and enter the number. If a technical data sheet gives tex or dtex, switch mode so the converter reads the source unit correctly. If you have a physical sample, use mass and length mode: weigh a known length of yarn in grams, enter the length in metres, and the tool will calculate both denier and tex.
Use the filament count when the construction matters. Denier per filament, often written DPF, divides total denier by the number of filaments. Two yarns can have the same total denier but different filament counts, which can change handle, opacity, strength and surface texture. The converter keeps total yarn count and DPF separate so a fabric buyer, lab technician or maker can read both numbers without mixing them.
Formula and Method
tex = denier / 9
denier = tex x 9
decitex = tex x 10
decitex = denier x 10 / 9
denier from sample = sample mass in grams / sample length in metres x 9000
tex from sample = sample mass in grams / sample length in metres x 1000
denier per filament = denier / filament count
The converter uses direct arithmetic and rounds only at display. That is useful when moving between specifications because a rounded tex value converted back to denier can otherwise pick up small differences. Keep more decimals for lab worksheets and fewer for product copy, labels or ordinary purchasing notes.
Common Denier to Tex Values
| Denier | Tex | Decitex | Example use | Reading note |
|---|---|---|---|---|
| 15D | 1.67 tex | 16.67 dtex | Very fine hosiery or lightweight sheer fabrics. | Small differences are visible in transparency and feel. |
| 40D | 4.44 tex | 44.44 dtex | Opaque tights, fine linings and lightweight synthetic yarns. | Often discussed by denier in retail descriptions. |
| 70D | 7.78 tex | 77.78 dtex | Light outdoor fabrics and backpack linings. | Coating and weave can matter as much as yarn count. |
| 210D | 23.33 tex | 233.33 dtex | Bags, lightweight packs, covers and utility fabrics. | Common benchmark for comparing fabric weights. |
| 600D | 66.67 tex | 666.67 dtex | Heavier bag fabric, upholstery-style synthetics and cases. | Do not compare durability by denier alone. |
| 1000D | 111.11 tex | 1111.11 dtex | Heavy-duty packs, workwear reinforcements and protective fabric. | Fibre, weave, coating and finishing also affect performance. |
Where Denier Can Mislead
A higher denier number means a heavier yarn per length, but it does not automatically mean a better product. A tightly woven 210D nylon with a strong coating can outperform a loosely woven heavier fabric in some uses. Polyester and nylon with the same denier can behave differently. Filament count, twist, weave, coating, finishing, abrasion testing and tear strength all affect the finished textile.
For clothing, denier often signals opacity or sheerness, especially in hosiery. For outdoor gear, it is one clue in a wider specification. For thread, it helps compare linear density, but needle size, seam type and fibre choice still matter. Use the converter to align units, then use the full data sheet for purchasing or testing decisions.
When comparing supplier quotes, ask whether the stated count is for the yarn before coating, the finished yarn, or the finished fabric. A coating can add weight without changing the base yarn count, while a textured yarn may occupy more space than a smooth filament yarn with the same denier. Record the unit exactly as supplied, then add tex or dtex beside it for internal comparison.
Sample Measurement Tips
Mass and length mode is helpful when you have a yarn sample but no reliable label. Cut a known length, condition it in the same room, weigh it on a scale accurate enough for small masses, and enter grams and metres. A longer sample reduces error because a 0.01 g scale error matters less over 90 m than over 1 m. Keep moisture and finish in mind, especially for natural fibres or coated yarns.
If you are testing production material, follow the relevant textile test method rather than a casual bench measurement. The calculator is a convenient arithmetic tool; the sampling plan, conditioning and scale accuracy decide whether the measured value is fit for a report.
FAQ
Is denier the same as fabric weight?
No. Denier is a yarn or fibre linear density. Fabric weight also depends on weave, yarn spacing, coating, finish and construction.
Why does 1 tex equal 9 denier?
Tex is grams per 1,000 m and denier is grams per 9,000 m. The denier length is nine times longer, so the denier number is nine times the tex number for the same yarn.
Can I convert denier to thickness?
Not directly. Thickness depends on fibre density, cross-section, twist and packing. Denier and tex measure mass per length, not diameter.
Sources
- International Organization for Standardization. (1995). ISO 1144: Textiles: Universal system for designating linear density (Tex System). ISO.
- International Organization for Standardization. (1994). ISO 2060: Textiles: Yarn from packages: Determination of linear density by the skein method. ISO.
- ASTM International. (2024). ASTM D1907/D1907M: Standard Test Method for Linear Density of Yarn by the Skein Method. ASTM International.