Threads are usually made up of several single strands twisted or plied together. The numbering system for threads has two parts: one related to the thickness of the single strand and the other to the number of strands (ply). Whereas the ply is expressed in thickness and the single strand is specified as a ?count? related to the length per unit weight. Cotton Count system, Tex system, and the Metric Ticket system are some of the commonly used thread numbering systems.


In this page

  1. Thread Size/Numbering System
  2. Common Numbering Systems

Thread Size/Numbering System

Threads are usually made up of several single strands twisted or plied together. The numbering system for threads has two parts: one related to the thickness of the single strand and 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 each 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 round 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 a 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.

Calculating the ratio of thicknesses for the Table

Instead of measuring the ratio of thicknesses of two threads, this can easily be calculated if they belong to the same numbering system. The diagram below may help you to follow the calculation. It shows how the cross-section area of a thread changes with thread number and ply.

You will see that it is easy to find the relative difference in cross-section area of two threads but, as we want to compare the thicknesses, it is the relative difference in diameter of the threads that we need. It may be obvious to some readers that this will be the square root of the ratios of ply/count for the two threads. However others may wish to check the logic of this below.

As an example, the percentage change in going from a 78/3 to a 35/2 thread is calculated:

This is the value that you will find in the table.

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 particular application is very important as it affects thread performance in a seam of 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 fibre is a pound of fibre. 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 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

Tex system

  • Lower the Tex, finer the thread
  • Higher the Tex, thicker the thread
  • Higher the Ticket, finer the thread
  • Lower the Ticket, thicker the thread

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 kilometre) 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 the Tex no is same. To convert Tex into 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 thread made from natural fibers and yarns. The size is 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 size 50 yarns. That has the same fibre 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 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 kilometres 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 kilometre hanks in one kilogram of synthetic thread. So size 100 is a fine thread and size 10 is extremely coarse.