Everything you need to know about Yarn

As knitters, we use yarn every day; yarn is part of our daily bread. But do we really know what yarn actually is? What is it composed of, how is it made, and how do the different qualities of yarn affect our final product? Read on to find out.

Yarn is a textile made from interlocked fibres. These fibres in their raw form are most commonly plant-based (hemp, bamboo), animal-based (wool, alpaca), or synthetic (viscose, polyester). How the yarn knits is affected by the fibre composition and so it is important to understand and consider qualities such as the weight of yarn before beginning your project.

Fibre Content

Fibre content refers to the material of the yarn. When you buy your yarn you will usually see a percentage on the label; 100% merino wool, or 50% cotton, 50% linen.

Bradford Count

The Bradford count measures the diameter of raw fibres. Thin fibres have high numbers and therefore hold a high Bradford count. This isn’t something that as a knitter you necessarily need to remember, however, the fineness of the fibre will relate to properties of the finished yarn.

Micron Count

A micron is one-millionth of a meter and is a measurement developed by the textile industry to measure diameter. Here, low numbers equal fine fibres. Cashmere and merino wool hold low micron counts, and so the lower the micron count will contribute to how soft a material feels.

Blood Count

Blood count is a method to measure the fineness of wool. It originated as a measurement of Merino within the sheep.


Denier measures the mass density of fibres and is based on the weight of a Roman coin. The bigger the number, the stronger the fabric. A single strand of silk is 1 denier.

Prickle Factor

The Wool Comfort Meter is a real thing! Developed by textiles manufacturers to measure how prickly wool feels on the skin. If a wool feels prickly it means that the fibres are not consistent. 


Yarn is created by twisting raw fibre strands together and this process is called spinning. There are three major processes of spinning: cotton, worsted, or wool.


When spun, single strands of fibres are twisted either clockwise (Z twist) or anticlockwise (S twist) in order to secure them. The twist helps give yarn it’s structure. Plying is where multiple strands are twisted.


Is the yarn plied, how many plies does it have, and how was it plied? The composition of the yarn will affect what you can do with it as well as the end result of your product. Novelty yarn such as bouclé make use of alternative plying techniques to achieve different effects.

Fibre Length

There is no measurement for fibre length, but it does affect how the yarn can be spun, what it can be blended with, as well as it’s warmth. Cotton is a short fibre, silk is long.

Yards Per Pound

The more yards per pound in a yarn, the finer it will be. This is a useful measuring tool when looking to substitute one yarn for another. The right substitution will be matching yards per pound.

Wraps Per Inch

A technique used to identify the weight of a yarn. Use an inch or yarn gauge to check the number of times you can wrap the yarn in an inch. The more wraps per inch, the finer the yarn. This can help you to select the correct needle size for your work.


There are 8 yarn weights, from lace to jumbo, numbered 0-7. The lower the number, the finer the yarn.

Weaving Count

Yarns produced for weaving are labelled with two numbers, referred to as the ‘count system’. This might be 20/2 linen yarn. The first number refers to the fineness of the single strand in the yarn. The second number refers to the number of plies.

Dye Lot Number

Yarns are labelled with a dye lot number.  From batch to batch colour can vary very subtly. Purchasing the same dye lot number ensures the yarn has been processed together and so the colour will be uniform.

Read Part 2 on the essentials of yarn, where we talk about selecting the right yarn for your project.

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