Have you ever been curious about what is actually meant by “40s”, “30 Denier” and “20 Tex” with yarn? They mark the density of yarn, most commonly called yarn count. Getting to know yarn count is necessary for textile students and professionals. It contributes to deciding the purpose, amount and type of yarn used for different applications.
In this post, we will explain what yarn count is, look at the two main systems—Direct and Indirect—show how to do the math and explain how to change between systems. If you’re gearing up for exams or are employed in industry, this guide will ensure you understand everything.
What is Yarn Linear Density?
Linear density refers to the mass per unit length or length per unit mass of yarn. In simple terms, it tells us how thick or fine a yarn is. Depending on the system used, the number either increases with fineness or coarseness.
This measurement is critical for:
- Yarn specification and classification
- Selecting yarns for weaving, knitting, or sewing
- Quality control and testing in mills
- Textile machinery settings
Two Systems of Yarn Count
Yarn count systems are generally divided into two categories:
1. Direct System
In the direct system, the count expresses the weight of a fixed length of yarn.
💡 Higher the count = coarser the yarn
Common Direct Count Units:
- Denier (Den): Weight in grams of 9000 meters of yarn
- Tex: Weight in grams of 1000 meters of yarn
- Decitex (dTex): Weight in grams of 10,000 meters
Formulas for Direct Count
Tex = (Weight in grams / Length in meters) × 1000
Denier = (Weight in grams / Length in meters) × 9000
These units are typically used for synthetic and filament yarns such as polyester, nylon, and viscose filament.
Usually for finding the count or linear density of yarn, we need two things.
They are:
- Length
- Weight
This is for both of the systems, to calculate the count of the yarn in a particular system we need to convert the units length and weight according to the system what we need or what we are going to calculate.
For example, If you want the count of the yarn in Tex but you have the length in yards and weight in pounds then you need to convert the units into the suitable form to use in Tex formula of the direct system since the formula for the Tex system is,
- Tex = (Weight in grams / Length in meters) × 1000
- Length in meters = Length in yards × 0.914 ( Because 1 yard = 0.914 meter ) or
- Length in meters = Length in yards / 1.094 ( 1 meter = 1.094 yards )
Now we need weight in grams according to the Tex formula so,
- Weight in grams = Weight in pounds × 453.6 ( 1 pound = 453.6 grams )
To do these conversions of course you should remember the length and weight measurements and basic units of length and weight.
Here is some important conversions to remember : ( * Important )
Linear System Measurements
- 1 inch = 25.4 mm*
- 1 inch = 2.54 cm*
- 1 mm = 0.03937 inch
- 1 cm = 10 mm*
- 10 cm = 3.94 inches = 1 decimeter
- 1 cm = 0.3937 inch
- 1 yard = 0.9144 meter*
- 1 foot = 12 inches*
- 1 inch = 0.0833 feet
- 1 foot = 0.3048 meter
- 1 yard = 36 inches*
- 1 meter = 39.37 inches*
- 1 meter = 1.0936 yards*
- 1 yard = 3 feet*
- 1000 meters = 1 kilometer*
- 1 kilometer = 0.6214 mile
Weight System Measurements
- 1 kg = 1000 g*
- 1 g = 1000 milligrams*
- 1 kg = 2.205 pounds (lbs.)*
- 1 lb = 0.4536 kg*
- 1 grain = 0.065 grams
- 1 metric ton = 1000 kg*
- 1 milligram = 0.015 grains
- 1 centigram = 10 mg
- 1 lb = 453.6 grams*
- 1 lb = 7000 grains*
- 1 ounce (oz) = 28.35 grams*
- 1 dram = 1.772 grams
- 1 metric ton = 0.984 ton
2. Indirect System
In the indirect system, the count expresses the length of a fixed weight of yarn. These systems define length per unit mass. Mostly used in spun yarns such as cotton, wool, and flax.
💡 Higher the count = finer the yarn
Definitions and formulas
1. English Cotton Count (Ne)
- Number of hanks of 840-yards of length present in one pound of yarn which means " How many number of hanks each containing 840 yards present in one pound of yarn".
- Formula: Ne = (Length in yards / 840) / (Weight in pounds) or
- (Length in yards x 453.6) / (Weight in grams x 840) or
- ( Length in yards / Weight in grams ) x 0.54
Note : **As I mentioned above in Direct system the given or found weight and length units can be whatever, you just convert them into suitable form to use in formulas, the given three formulas are the easy and basic formula with that you can calculate the counts effortlessly if you are strong in conversions of units, so it is recommended to go through the given important conversions.**
- Example: 40s Ne = 40 × 840 yards in 1 pound = 33,600 yards/pound.
2. Metric Count (Nm)
- Number of hanks of 1000 meters of length present in one Kg of yarn.
- Formula: Nm = (Length in meters / 1000) / (Weight in kg) or
- (Length in meters / Weight in grams )
- Use: Common in European and scientific measurement systems.
3. French Count (Nf)
- Number of hanks of 1000 meters of length present in 500gms of yarn.
- Formula: Nf = (Length in meters / 1000) / (Weight in grams / 500) or
- Length in meters / (Weight in grams x 2 )
4. Worsted Count
- Number of hanks of 560-yards of length present in one pound of yarn
- Formula: Worsted Count = (Length in yards / 560) / (Weight in pounds) or
- (Length in yards x 453.6) / (Weight in grams x 560)
- Use: Mainly for long staple wool yarns.
5. Linen Count (Lea or NeL)
- Number of hanks of 300-yards of length present in one pound of yarn
- Formula: Lea = (Length in yards / 300) / (Weight in pounds) or
- (Length in yards x 453.6) / (Weight in grams x 300)
- Use: Specialized for flax yarns and linen.
6. Woollen Count
- Number of Skeins of 1536 yards of length present in 6 pounds of yarn.
- Formula: Lea = (Length in yards / 1536) / (Weight in 6 pounds) or
- Length in yards / ( weight in pounds x 256 )
- Used for: Woollen yarns
How to Convert Between Count Systems
Indirect ↔ Direct Conversion
You may often need to convert from one system to another. Here's how:
(some important conversions )
Ne to Tex and Tex to Ne:
Tex = 590.5 / Ne and Ne = 590.5 / Tex
Ne to Denier and Denier to Ne
Denier = 5315 / Ne and Ne = 5315 / Denier
Denier to Tex and Tex to Denier:
Tex = Denier / 9 and Denier = Tex × 9
Nm to Tex and Tex to Nm:
Tex = 1000 / Nm and Nm = 1000 / Tex
Ne to Nm and Nm to Ne:
Nm = Ne x 1.694 and Ne = Nm x 0.594
Ne to Nf and Nf to Ne:
Nf = Ne x 0.874 and Ne = Nf x 1.181
Ne to Nw and Nw to Ne:
Nw = Ne x 1.5 and Ne = Nw x 0.667
- If you remember all these formulas then you can get any count from a given or known count of yarn.
- These formulas are helpful for exam prep and machine calibration, especially when dealing with blends or comparing imported yarns.
Why Understanding Yarn Count Matters
Whether you're a spinning supervisor, quality control engineer, textile student or merchandiser—count helps you understand:
- Yarn fineness
- Fabric GSM (grams per square meter)
- TPI (twist per inch)
- Coverage and fabric appearance
- Yarn strength vs. fineness trade-offs
Important Technical Points You Should Remember
- Count is inversely proportional to thickness in indirect system
- Count is directly proportional to thickness in direct system
- Tex is becoming a universal standard, especially in ISO systems
- For blends, the count system used is typically the dominant fiber’s system
Commonly Used Count Systems by Fiber Type
- Cotton: English Count (Ne)
- Wool: Worsted Count
- Silk: Denier or Tex or Ne
- Linen: Lea
- Synthetic Filaments: Denier or Tex
- Blends: Sometimes converted to Tex for uniformity
Advanced Industry Note
Many modern yarn manufacturers now label yarns with multiple count systems (e.g., 30 Ne / 20 Tex) to serve global buyers. Also, smart yarn production software can auto-convert counts, but it's vital for humans to understand the basics for troubleshooting, planning, and auditing.
Applications in Real Life
- Fabric Manufacturing: Warp & weft yarns are selected based on desired GSM and texture
- Spinning Mills: Count helps determine roving requirements and spindle speeds
- Knitting: Count affects loop density and elasticity
- Testing Labs: Yarn count is measured for batch acceptance and fabric planning
FAQs: Yarn Count and Linear Density
Q1. What is yarn count in simple terms?
It’s a number that tells you how thick or thin the yarn is, either by weight per unit length or length per unit weight.
Q2. Which is coarser: 10s Ne or 40s Ne?
10s is coarser. In the indirect system, smaller numbers mean thicker yarn.
Q3. Is Denier a direct or indirect system?
Direct. It tells you how much 9000 meters of yarn weighs in grams.
Q4. Can yarn count affect fabric feel?
Absolutely. Finer yarns (higher Ne or lower Denier) give softer, smoother fabrics.
Q5. Why do we need conversions?
Different industries and countries use different systems. Conversions help compare and standardise yarns globally.
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Final Words
Understanding yarn count isn't just about remembering formulas—it's about feeling the textile through numbers. Whether you're a student preparing for competitive exams like SSC JE, GATE (TF), or working on fabric planning in a mill, mastering yarn linear density gives you a huge advantage.
"Textile is a language, and count is its grammar."
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