Yarn Count Converter: Ne, Nm, Tex, Denier and Dtex

How to use

This converter turns a count you know into every system, or works out the count from the length and weight of a skein. With JavaScript turned off, press “Calculate”.

1. Under “Calculation”, choose “Convert a count”.
2. Enter the value in “Yarn count” (for example, 30) and pick its system in “Count system”: tex, dtex, denier, Nm, Ne (English cotton), NeK (worsted) or NeL (linen lea).
3. For a plied yarn, enter the number of plies in “Number of plies”; the count field takes the count of a single ply (30 and 2 for Ne 30/2).
4. For a filament yarn (continuous filaments), fill in the optional “Number of filaments” to get the denier and dtex per filament too.

To find a count from a measurement, choose “From a skein” and enter the skein length (meters or yards) and its weight in grams. The result panel shows all seven systems at once, with up to two decimals and trailing zeros dropped (50.8, not 50.80).

Formula

Every conversion goes through tex: the count is converted to tex first, then to the system you want, so no separate formula is needed for each pair of systems. Ne and Nm are length-based (indirect) systems: a higher number means a finer yarn. Tex, dtex and denier are weight-based (direct) systems: a higher number means a thicker yarn (Cotton Incorporated, TRI 1014).

The constants follow from the hank lengths (840 yards for cotton and 560 for worsted in TRI 1014; 300 for linen in Swicofil) and from the exact definitions 1 yard = 0.9144 m and 1 pound = 453.59237 g (NIST Handbook 44, Appendix C): for cotton, 1,000 × 453.59237 ÷ (840 × 0.9144) = 590.54. Directly, Nm = 1.6934 × Ne, NeK = 1.5 × Ne and NeL = 2.8 × Ne. TRI 1014 rounds these to 590.5 and 1.693, so hand calculations with rounded factors differ slightly in the last digit.

From a skein to a count

tex = weight (g) ÷ length (m) × 1,000 and Nm = length (m) ÷ weight (g) (MEB, 2014; Çukurova University lab sheet). A length in yards is converted first: meters = yards × 0.9144.

Worked example

The tool's default value is a Ne 30/1 cotton yarn (single ply):

1. tex = 590.54 ÷ 30 = 19.68 (raw value 19.6847)
2. dtex = 10 × 19.6847 = 196.85
3. denier = 9 × 19.6847 = 177.16
4. Nm = 1,000 ÷ 19.6847 = 50.8
5. NeK = 885.81 ÷ 19.6847 = 45 and NeL = 1,653.52 ÷ 19.6847 = 84

Result: Ne 30/1 = 19.68 tex = 196.85 dtex = 177.16 denier = Nm 50.8 = NeK 45 = NeL 84. Nm 50.8 means that 1 gram of yarn is about 50.8 m long. The tool rounds only for display: if you carry on from the rounded 19.68 tex, you get 196.8 dtex and 177.12 denier.

From a measurement: a 100 m skein that weighs 2 g is 2 ÷ 100 × 1,000 = 20 tex, which is Nm 50, 180 denier and Ne 29.53.

Common yarn counts: Ne to tex, dtex, denier and Nm

The table lists frequently used Ne values with their equivalents. The Ne 20 row, for example, reads 29.5 tex, 295.3 dtex, 266 denier and Nm 33.9.

Filament yarn: denier to dtex, tex, Nm and Ne

Filament yarns are mostly sold by denier or dtex; the table converts common deniers.

Trade names are rounded: 150 denier is exactly 166.67 dtex, but trade lists often write it as 167 dtex, and 167 dtex is 150.3 denier. Total denier and denier per filament also differ. With 48 filaments, a 150 denier yarn has 3.13 denier per filament (3.125, rounded half up) and 3.47 dtex per filament.

Plied yarn counts: how to read and convert 30/2 and 20/2

In cotton yarn notation, the number left of the slash is the count of a single ply and the number on the right is the number of plies: Ne 30/1 is a single yarn and Ne 30/2 a two-ply yarn. The tool assumes that all plies have the same count and gives the resultant (equivalent) count.

• Ne and Nm: resultant count = single-ply count ÷ number of plies. Ne 30/2 → Ne 15, which is 39.37 tex and Nm 25.4. Ne 20/2 → Ne 10 (59.05 tex).
• Tex and denier: the plies add up. 20 tex × 2 → 40 tex; 100 denier × 3 → about 300 denier (TRI 1014).

The calculation ignores twist, which has a small effect on the equivalent count (TRI 1014); measure the plied yarn for an exact value. Notation also varies: in some systems the written number is that of each ply, in others that of the whole yarn (TRI 1014). In a specification, write the count and the number of plies separately.

Common mistakes when converting yarn counts

1. Leaving out the system. A Ne 30 yarn is 19.68 tex and an Nm 30 yarn is 33.33 tex, about 1.7 times heavier per meter. A quote that says only “30/1” can be misread.
2. Using Ne for every fiber. Ne is the cotton system. The same yarn is NeK 45 on the worsted system and NeL 84 on the linen system (Ne 30). For non-cotton yarn, choose its own system.
3. Mixing up tex, dtex and denier. dtex = 10 × tex and denier = 9 × tex; using one for the other creates an error of about 10–11%.
4. Treating a converted value as the governing value. An Nm 50 yarn is 20 tex and a Ne 30 yarn is 19.68 tex, a gap of about 1.6%. If a supplier delivers one instead of the other, that is a substitution. Mark converted values “approximate” in the specification.
5. Taking the stated count for the measured count. The formula is exact; the input is the stated count. Dönmez (2008), a master's thesis at Dokuz Eylül University in Turkey, measured a combed cotton (penye) yarn stated as Ne 30 ten times and found Ne 28.37 to Ne 28.84. It is a single study and should not be generalized, but it shows that stated and measured counts can differ.

Standards and measurement

The conversion is pure arithmetic; moisture, twist and fiber type do not enter it. Yarn weight does change with moisture, so condition a sample in the standard atmosphere (20 °C, 65% relative humidity; ISO 139) before you measure. Yarn on packages is tested by the skein method (ISO 2060:1994): a 100 m skein for tex and Nm, a 120-yard skein for Ne (Çukurova University lab sheet). ISO 1144:2016 defines tex as the universal designation for all fibers and yarns. ISO 2947:1973 lists rounded tex values for traditional counts; this tool uses the exact factors, so its results can differ slightly from them. ASTM D2260 tabulates conversion factors.

Have a count that will govern a contract determined by a test laboratory. To find a yarn supplier in Turkey, see cotton yarn, polyester yarn and blended yarn companies. The yarn count conversion guide covers how a count shows up in the fabric and how to write it into a specification; for fabric, see the fabric GSM calculator and the fabric meter to kg calculator.