When it comes to judging the carpet quality, the fineness of the knots or its density is a very important criterion to consider. The fineness of the carpet is dependent on the strength of thickness of the wool that is used in the making of the carpet. It depends upon the strength of warp threads that are constrained length-wise.
The measurement of the yarn density is done per square meter by counting the number of knots in both vertical as well as horizontal direction. The range is quite diverse, reaching to 100,000 knots per square meter for rougher carpets and going to about 1,500,000 knots per square meter for fine carpet varieties.