Wool from different sheep breeds is divided into three main categories (broad, medium and fine) based on the diameter (fineness) of the wool fibre, measured in microns. Within the wool industry, the terms broad, medium and fine can be used ‘loosely’. There are some differences in the application of these terms with different sheep breeds and crossbreeds. However, the ranges shown here represent a loose consensus within the global wool-growing industry.

Broad 

(more than 29µm)
Breeds such as the Romney produce long, medium-lustre wool, which is particularly useful for carpets and furnishings because of its strength and durability.

Medium 

(23 – 29µm)
Breeds such as the Corriedale produce medium wools used in a variety of woven apparel cloths, knitting yarns and furnishings. A wide range of medium wools has been produced by crossing one breed of sheep with another.

Fine 

(less than 23µm)
Although some non-Merino breeds produce wool in the range of 23µm, wool with the finest micron comes from Merino sheep.

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