Yarn/Thread Count Numbering System

Since all yarns have circular cross section and are not easily deformed during measuring, measuring the yarns are trickier. The accepted way to indicate the thickness of a yarn is to use the linear density.

Yarn numbering systems are used to express relationship between unit of length and weight of yarns which also reflects the diameter or thickness of yarn.

In the case of long staple yarns, whose technology is derived from one of the processes for making yarn out of wool, a hank is often defined as 560 yds. of yarn, and in this case, the symbol NW will be used to describe count.

Threads are usually made up of several single strands twisted or plied together. The numbering system for threads has two parts:

1. one related to the thickness of the single strand and
2. the other to the number of strands (ply). Whereas the ply is expressed in a straightforward manner, the thickness of the single strand is not specified directly but as a ‘count’ related to the length per unit weight.

Thus, a 30/2 thread (Nel) is a two-ply thread, and every single strand measures 30 x 300 yd/lb. Note that the ‘count’ is inversely related to the thickness — the higher the count, the thinner the thread. So a 30/2 thread is thinner than a 20/2 thread. (Obviously, for a thread of a particular count, the thickness will be directly proportional to the ply — the higher the ply, the thicker the thread. So a 35/3 thread is thicker than a 35/2 thread.)

Yarn Numbering Systems

Textiles are often sold on a weight basis and consequently it is natural to express the size of “thickness” of a yarn in terms of weight (or mass). There are two basic ways in which this may be done. These are:

1. By saying how much a given length of yarn weighs or commonly known as Direct Systems,where the Length is constant and Weight is variable.thus, the tex is the weight in grams of 1 thousand meters of yarnand, denier is the wight in gams of 9000 meters of yarn
2. By saying what length of yarn one would have in a given weight or commonly known as Indirect Systems, where the Weight is constant and Length is variable.thus, the English Count (Ne) is the number hanks of 840 yards in length that weigh one pound in weight.and, Worsted Count is the number of hanks of 560 yards in length that weigh one pound.and, Metric Count is the number of kilometer lengths that weigh one Kilogram.

Direct Systems

The technical name used to describe the yarn size in the direct system is linear density,* and this is always expressed in terms of weight/unit length also terms as “Yarn Number”.

The scientific subsystem uses the unit “tex,” where 1 tex is the weight in g of 1000 meters (1 km) of yarn and the number gets bigger as the yarn gets fatter. Thus, a 50 tex yarn weighs 50 g for every kilometer of yarn. The normal metric prefixes of kilo, deci, etc., can also be applied to the unit tex. Hence 1 decitex is 1/10 tex and 1 kilotex = 1000 tex.

The fiber industry tends to use the unit “denier” where 1 denier is the weight in g of 9000 meters of yarn. Thus a 450 denier yarn weighs 450 g for every 9000 meters. A moment’s reflection will show that the two examples given refer to the same yarn size. Denier is very often used to describe the size of the fiber; hence, a 1½ denier filament weighs 1½ g per 9000 m of that filament. In passing it might be noted that if the 450 denier yarn is made up of 1½ denier filaments, there will be 450/1½ = 300 filaments making up that yarn.

Indirect Systems

It will be remembered that the indirect system is in terms of length per unit weight. Generally, all the subsystems in this category are referred to as yarn count or yarn number, and it is necessary to specify the subsystem.

The units developed in England during the industrial revolution are still used in the USA. In this case, a hank is specified as containing 840 yds* of yarn. Thus, if the count of a singles yarn is 20 hanks/lb. (usually written as 20s or 20/1), there will be 20 x 840 yards in a pound of yarn. The symbol used in this bulletin will be Ne where the subscript refers to
“English” and distinguishes it from Nm, which refers to the metric count (meters/gram).

In the case of long staple yarns, whose technology is derived from one of the processes for making yarn out of wool, a hank is often defined as 560 yds. of yarn, and in this case, the symbol NW will be used to describe count.

Threads are usually made up of several single strands twisted or plied together. The numbering system for threads has two parts:

1. one related to the thickness of the single strand and
2. the other to the number of strands (ply). Whereas the ply is expressed in a straightforward manner, the thickness of the single strand is not specified directly but as a ‘count’ related to the length per unit weight.

Thus, a 30/2 thread (Nel) is a two-ply thread, and every single strand measures 30 x 300 yd/lb. Note that the ‘count’ is inversely related to the thickness — the higher the count, the thinner the thread. So a 30/2 thread is thinner than a 20/2 thread. (Obviously, for a thread of a particular
count, the thickness will be directly proportional to the ply — the higher the ply, the thicker the thread. So a 35/3 thread is thicker than a 35/2 thread.)

Comparing threads for changing patterns

The key point in comparing threads for changing patterns is that the thickness of the thread is its diameter. When reducing or enlarging a pattern, the diameter of the thread should be changed by the same amount so as to keep the ratio between the diameter and the size of the pattern
constant.

Measuring the ratio of thicknesses

The most obvious way of comparing the thickness of two threads is by measuring their diameters. It is easiest to do this by winding the thread around a ruler and measuring the number of windings over a certain length. To obtain the diameter divide this length by the number of windings.

Consider as an example that we wish to change from an 80/2 thread to a 35/2 thread. When we wind these round a ruler we find that for the 80/2 thread there are 30 windings per cm, whereas for the 35/2 thread there are 20 windings per cm (shown on the right). Thus, the 80/2 thread is thinner than the 35/2 thread by a factor of 20/30, i.e. it is 67% as thick. (Conversely, the 35/2 thread is 150% the thickness of the 80/2 thread).

Although the method is not exact because one person may wind more tightly or loosely than another if the same person makes both windings the result will be accurate enough in practice.

For sewing industry, all threads can be produced in different thicknesses and the size of a particular thread is the relationship of its length to its weight with exception of Monofilament threads. This relationship of length to weight is known as linear density, yarn count, or size.

Selection of correct thread size for a particular application is very important as it affects thread performance in a seam of the garment. There are fixed weight systems which measure how much thread weighs a given amount, and fixed length systems which measure how heavy is a given length of thread.

A pound of fiber is a pound of fiber. It has the same amount raw material in it, no matter how coarsely or finely its spun. Because thread sizing is based on weight, threads made from different materials can be different in size but have the same number (or have the same size but different numbers). Cotton count system, the Tex system, and the metric ticket system care the ones most often used in general sewing.

Equivalent Size

The same size thread can be constructed using different count yarns by varying the number of plies. 30/2 or 45/3 or 60/4 is physically the same size threads. To determine the equivalent size, simply divide the yarn count by the number of plies. All three of these threads have the equivalent size of 15.

Common Numbering Systems

Yarn Count Conversion Calculator

Tex system

Tex system is symbolized by (Tex) and is a direct count of thread weight per unit length. It is based on the weight in grams of a thread 1,000 meters (1 kilometer) long. 1,000 meters of Tex 10 (very fine) thread weighs 10 grams, while 1,000 meters of Tex 100 (very coarse) weighs 100 grams. The Tex system measures the entire thread, no matter how many strands or plies it has.

Ticket number

is a system to give easy approximations of the specific size of finished thread and is different for different thread types even if Tex number is same. To convert Tex into the ticket (1000/Tex No) x 3.

Cotton Count system

If you had a single strand of yarn 840 yards long weighing one pound, its count (or size) would be shown as 1/1. This simply means it had a count of one (the first number) and that it was a single strand or yard (the second number). If you then twisted two or those single strands together, the size would then be ½: One count yarn (the first number), in a two ply construction (the second number).

is used for threads made from natural products and is symbolized by Ne. It is based on the number of 840 yard hanks in one pound of the thread made from natural fibers and yarns.

The size is a measure of an individual yarn or strand. Most threads are made from multiple strands or plies. In the cotton count system, 50/2 designates a two-ply thread made from two sizes 50 yarns. That has the same fiber contents as one size 25 yarn. 8,400 yards of size 10 (coarse) or 84,000 yards or size 100 (extremely fine) is same for one pound of the cotton yard in this system. Cotton Count System (Ne) has been the accepted standard in sizing spun threads.

The Hong Kong ticket System

is the same as the cotton count system, just written without the slash. So a cotton count 50/2 thread is a Hong Kong ticket 502 thread.

Denier System

is used for continuous filament synthetic threads and is symbolized by d and is based on the weight in grams of a thread 9 kilometers long.

Denier measurements are nine times larger than Tex for the same yarn. However, denier is sometimes applied to individual strands of a multi-ply thread, while Tex is always applied to the entire thread. Denier sizes are usually written as 1000d, 200d, and so on.

Metric Count System

is used for synthetic threads and is symbolized by Nm and is based on the number of 1-kilometer hanks in one kilogram of synthetic thread. So size 100 is a fine thread and size 10 is extremely coarse.