The fineness or density of the knots is one of the most important criteria to judge the quality of a carpet, if not the decisive one. The fineness of a carpet depends generally on the strength of the lengthways-strained warp threads and the thickness of the wool yarn used for the pile. The knotting density is counted in the number of knots (in horizontal and vertical direction) per square meter. It can reach from 100.000 knots/qm for a rough commodity, up to 10.800.000 knots/qm for the finest carpets.
In the praxis one can refer to the following definition:

very coarse	40.000 - 80.000 Knots/m2
coarse	80.000 - 120.000 Knots/m2
middle fine	120.000 - 250.000 Knots/m2
fine	250.000 - 500.000 Knots/m2
very fine	500.000 - 1.000.000 Knots/m2
extremely fine	1.000.000 - 4 Million Knots/m2
rarely fine	above 4 Millon Knots/m2